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Good evening, ladies and gentlemen and welcome once again for

Prof.Devons: rs seupaninshtats vineaee

a brief interval to this meeting of the Symposium on the
Relationship of Biological and Physical Sciences. This
Symposium is, as you know, supported by the NYState Founda-
tion for Science & Technology. This meeting we have this
evening is a delayed pleasure - it's been our ninth meeting
Unfortunately Dr. Nirenberg was ill on that occasion and
he had to disappoint to you. I am glad to say, as you can
see for yourself , he is here and well this evening and
will talk to us tonight, and I am going to ask Professor
I. I. Rabi , University Professor of Columbia University
to introduce our speaker this evening.

Prof Rabi:
Ladies and Genglemen , Dr. Nirenberg deserves a very much
better introducer than he is getting.tonight. Because I am
no kind of biologist - I call.myself a physicist - my only
connection with biology ina practical way was to plant a few
trees some 50 years ago , in Brooklyn of course, (laughter)
but I am very glad to introduce Dr. Nirenberg . In the first
place his subject doesn't sound very biological to me on
the translation of the genetic code - either physics or linguistics
~ now Dr. N. was born in New York and when he was a helpless
little boy was taken down to Florida, where he grew up and
proved that we get things from Florida, good things from,
Florida apart from grapefruit and suntans. He was graduated
from the University of Florida in 1948 and then got an M.A.
there and finally worked his way north to get a doctor's
degree from the University of Michigan. I will not recount
muhh further in his career or the various things which he

did because £xex actually I couldn't put the proper feeling
-2-

into the topics for which he became justly famous. He's a
young man, by my standards, and the year 1965 was an extra-
ordinary year for him - probably the opening guns for a still
more extraordinary career following - but I note in this
biography given me that he became an Honorary Doctor of Science
in the University of Michigan , Yale University, and the
University of Chicago - all in one year and received a National
Medal of Science from the President of the United States in
that very same year, in addition to becoming a fellow of the
American Academy of Arts & Sciences. What 1966 will bring
for him I don't know - it has probably brought a great deal
already but it's not on the record which I have. I happened
to be present when the discussions were taking place for the
nomination for this distinguished National Medal of Science
and all agreed that man had wery great talent indeed and I
join with you in looking forward to his talk which would be
as I said on the Translation of the Genetic Code. (Applause
Dr. Nirenberg:
Thank you Dr. Rabi. Having been born in Brooklyn I also want
to-thank--you-for. having. planted some trees in Brooklyn . I
am~gilad-really to have this opportunity to tell you about the
genetic..lang ; ot perhaps 2 to @ billion years continuous
dialogue between cells and their descendants has taken place.

/sach generation passes to the next a library of information

which specifies in detail the way to make many kinds of

 
» < Sat s _ -
A - . Y ‘ ye 3 (
ee ELLE , ee
of/life on this .planectasenaegiict use viresalty, ‘the same planguage
pe he eo . THe,

atthough recent ty severat = a humber of alayects have 3 bean!
found-thet-#1 41 desertbe-tater.—

May we have the first slide please - This -
Very-good - The last slide was a good ihtroduction anyway
to introduce some of the collaboratores who have worked on
this problem in the last - oh 3 years I guess - 4 years
This in a very real sense has been a collaborative project
and I would like to call attention to these - to the collab-
orators. However, this is the last slide and I think if we
could have the first slide (laughter ) we will show it again
xakex at the end. Good - this is an illustration from
Watson's recent very fine book which diagramatically illus-
trates a double strand of DNA and an enzyme RNA preliminaries (?)
which cahalyzes the synthesis of message RNA as shown here.
The point that I wish to make here is that only one strand
of the DNA is copied by RNA prelimnates - is copies with a
given polarity not known really what signals or what words
specify the beginning and the end of the message RNA synthesis
But there must be a code word of some sort which says Start
and another one that says Stop. These remain to be defined.
Next slide please
This shows also diagramattcally a protein synthesis DNA shown
here and the different cross hatches represent various segments
of DNA corresponding to - each corresponding to a prote&n
possibly or several proteins - messenger RNA ribozomes dia-
grammatically attached to the messenger RNA and reading begins
and as soon as one moves down another one attaches until the

message is virtually covered with ribozomes.
-4-

The reading takes place by means of SRNA, transfer RNA
which carries specific amino acids and recognize particular
code words on the ribozomes. Thus, the code word is recog-
nized not by the amino acid per se, but by an adaptor mole-
cule , adapter SRNA. Now, the rationale coeeeky for our
previous work on the code was to use synthetic messages
- compared with polynucleic type sporelegs ? they were
randomly ordered sequences messages, and in this way
characteristics of the code could be determined. And also
base compositions of code words. But not base sequences.

The situation up to one - well, two - years ago was very

much like that of an anagram. We knew the letters of the

code , but not the order, of the letters within each word.
Now, an approach towards determining the sequences of the

code words, are shown on the next slide.

This illustrates diagrammatically again the code on recog-
nition process. This is a ribozome of E coli small sub-unit
and large sub-unit . There are two binding sites for

SRNA at least per ribozime, shown diagrammatically here, and
this shows an amino SRNA presumably three bases in the trans-
fer RNA molecule recognized and three bases in the message
RNA which binds to the small sub-unit and amino acid as shown
here. Now one of the binding sites presumably is for the
peptftal SRNA which is shown here. The other for the incoming
amino S-less RNA. Three enzymes plus GTP are required for

the transfer, then, of the growing peptide chain to the next
amino acid. A shift in some way occurs so that the next three
bases would be read. Thus protein synthesis starts at a given

place and proceeds, reads three bases sequentially and reads
-5-

with a given polarity. Next slide please ..

Well, actually in several laboratories, Schweets labo-
ratory, Lippman's laboratory, Rockefeller, KG's , it is
shown that if one added a synthetic message RNA, such as
polyuradylic acid , to ribozomes, that phenalalamino SRNA
bound to the ribozomes prior to peptide bonds synthesis,
my colleague Dr. Philip Lieder, and I wondered how small
a message would direct the binding of the SRNA to the
ribozome and it turned out that only three bases were needed.
That is, the triplet itself would direct the binding of the
appropriate aminoSRNA to ribozomes . This provided a rather
simple route towards determing the sequence of RNA code
words. Now our major problem was to devise some techniques
for synthesising triplets. At the time we started the work
with the triplets a - oh perhaps 20 to 25 of the 64 possible
permutations of bases were reported, had been either prepared
by enzymatic digestion of RNA or by chemical synthesis, by
some of the very elegant techniques devised by Karana and his
associates . Two techniques were developed in our laboratory
the first by Philip Lieder, Maxine Singer and Richard Rimakome
employed polynucleic type phosphoralays which requires a doublet
primer illustrated here, and adds nucleic psydiphosphates to
this to make triplets,tetramers, pentamers and soforth. A
second methdd developed by Merton Bernfield in our laboratory
which employed an observation that had been made by Heppel
some years before. The pancreatic RNA-ase which is normally

thought to be degradative enzyme will catalyze a transister -

ification from a two-prime, three-prime cyclic nuclear dite
-6-

to a five-prime hydroxol to form triplets and higher homolons.

Thus, this technique added units to the left end of an accepter

and the polynucleic type phosphoral aids added units to the

right end of an accepter. With these two techniques it became

rather simple to compare various triplets needed.

The next slide please ..

Now this just shows diagrammatically an oligonucleitide and

I wish to illustrate only that ... a given segence , say,

triade, may exist in three chemically distinct forms, depend-

ing on its geography. in a molecule, that is, a five-prime

terminal code-on, internal code-on, and“three-pr ime terminal

code-on. All of our evidence todate indicates then that the

biologic characteristics of the code-on recognition may in

some cases .. many cases .. be influenced by the particular

position of the code-on. Thus, each of the 64 possible

triplets may exist in three different structural forms.

Next slide please ....

This shows the influence of various substitutions on the

hydroxyl groups - terminal hydroxyls of the sugar. This

is a concentration of oligonucleitide plotted against the

binding aphenymekaikxxe aphenylalaminecern into ribosols.

A simple triplet of tri-U has an activity such as this -

if one adds a phosphate to the a eree hydroxylake the

sugar the template activity is greatly enhanced, Shown here.

A phosphate attached Hmex# to the three-prime terminus lowers
Rotman

template activity., Recently Fritz Roten in our laboratory

prepared some attalogs of tri-U also mmkaxz with a metal group

attached to the five-prime phosphate , shown here, and
-7-

this is, although this should be CH, it's a metal group also

3
attached to the three-prime phosphate. Three-prime terminal
phosphate. And this greatly reduces template activity.
A triplet with a two-prime three-prime cyclic phosphate
has very little template activity. Next slide please

We think it possible that terminal hydroxyls of sugars
may be modified and that in some cases, possibly these may
regulate the template activity of the code-on. The...
certainly a substitution at the five-prime terminus may be
important because this may serve as a signal which specifies
the attachment and/or detachment of the ribozome to the
message. Recently, Matra and Herwits , also Stent, have
shown in vitro, at least, that messenger RNA contains a
triphosphate attached to the five-prime terminal hydroxl.
And, although it's not clear what the £Hnsakxanxmk physio-
logical funcation of the triphosphate is, it's highly possible
that this may in some way specify the phasing, the initiation
of reading of the message . It would also select the first
word to be read, phase the reading and perhaps affect the
susceptibility to m=xnHgeksagenks exonucleasis. Internal code-
ons may be also important , may be modified in various ways
two-prime hydroxyl, or the base could be modified ... I
think that code-on neighbors may in some cases play a role
also in ... may affect the code-on recognition process.

I would also like to call attention to the possible
difference hetween internal initiation and termination
vs terminal initiation and termination. The mes...
often messages ... messenger RNA seems to contain the infor-

mation from more than one purtsing ? if one starts reading
-8-

at/left end forthe terminal initiation one reads in and then
comes to a word that says Stop and an unknown mechansim for
starting an internal position. And .. that so that internal
initiation and termination may, it's not known, but it's
possible that it may be different from a terminal initiation
or termination.mechanism. Next slide please ...

On this slide is plotted oliganucleitide concentration
and binding of aminoacelesito ribozomes. I wimply want to
illustrate several points that became obvious very early in
thiswork. First, that synonym code-ons corresponded to
various aminoaceles RNAs , for example, phenylalemine SRNA
responded to both to UUU and UUC. And UUC was slightly
more active than UUU. With light CSRNA responded to AAA and
AAG there was a quite marked difference in template activity
of each synonym. The degeneracy that was observed was a
very logical degeneracy because the C=U in the third position
and in this case, A=G in the third position. Next slide please...

On this slide is summarized virtually all of our work to
date. We have synthesized 63 of the 64 possible triplet se-
quences and the sequences of RNA code-ons are shown. The
underlining represents previous base composition assignemtns
which were done with the protein synthesizing system and
randomly ordered pinucleitides. And we've observed a very
close correspondence between the earlier work with randomly
orderéd polynucleitides and base sequence studies. I should
point out the types of synonymi that are observed. For example,

glutannic acid corresponds to code-on ... GAA and GAG. Aspartic

acid .. GAU GAC Uc AG type of degeneracy. Another type of
-9-

degeneracy is illustrated in this column where the third posi-

tion may be occupied by either UC A or G, completely variable.

Another type of degeneracy is illustrated by methianate, that

is a G may be present in the third position, may be recognized

but not in A. I think that the logical degeneracy that has

been found has its many consequences, one of the more obvious

is that one may have a great deal of silent mutation, that

is in one of the , one of the code words or groups of synonym

code .. code-ons one may have mutation and ... which may

convert any base in the third position to any other base

without resulting in amino acid replacement in per ?

Another obvious conclusion is that amino acids which are

very Similar chemically such as aspartic acid, and glutanic

acid , both dicarboxcylic acids, have chemically similar,

quite related code-on. It may reflect the evolu tion of the

code , it's not clear, but certainly one consequence would

be that when error does occur, usually two bases are read

correctly , one incorrectly. And very often a chemically-

may be

related amino acid xs substituted in protein when an error

does occur. Thus the general picture of the code is quite

a conservative one .. one that minimizes error most often.
There's one underlying question though which has not

yet been answered, and that is, why ... why does one see this

type of code ... why shouldn't phenylalimine, for example,

be corresponding to GCU and GCC instead of alimine. This

question has not been answered and I think that there may
~10

well be a chemical meaning to this. It is not obvious yet
Alternatively, it ... simple chance alone may acoount for this.
I tend to think, however, this is ... is a personal preference
--. that there will be an underlying meaning will be found.
Next slide please....

Could we have that last slide ... just a second ...

I wanted to point out the ... previous slide ... I wanted to
point out that some code words may ... appear to serve special
functions. For example, the recent work of Brenner, Garen,
Zinder and others indicate that UAA and UAG may specify the
end of the message, although the precise mechanism for punctu-
ation is not known. UUG and CUG AUG and some cases GUG
May correspond to the initiation .. may specify the start

Our recent studies, and those also of CLark and Marker in
England , have indicated that these code-ons in terminal
positions at least, are recognized by enformulesionate

and this may serve as an initiator of protein synthesis.

I'll say more of special function words and .. in a few
minutes. Let me have the next slide please ...

This simply summarizes the various patterns of synonym
code-ons that are observed. You would see in the third posi-
tion , and so forth. The enformulathiamine SRNA the initiator
Next slide please ...

Some possible special function code-ons are listed on
this slide. Sanger in England first observed the necoli
that one of the two speciss, or at least a part of methianine

SRNA could accept a formula moiety.
-1l1-

The amino group of the methianine after the methianine was
linked to the SRNA could be formulated. And the work of
Kapetchy and his colleagues in Watson's laboratories and
others have suggested, Zinder's Lab also, have suggested
that this may specify initiation . And as I indicated before,
U UG AUG CUG and to some extent also GUG are recognized by
the informulinine SRNA. UAA UAG may serve as a terminator,
we think it likely also that AGU AGC AGA also AGG may serve
as special function words. The functions , however, have
not thus far been found. This is, I think, the situation
now is extremely interesting because the tools are to hand
to try to decipher the mechanism of special function words
and also the various functions that they may play in protein
synthesis.

Next slide please ... Dr. Hatfield in our laboratory
has recently prepared some radioactive triplets and have
looked at the binding of the triplet to the ribozome. In
this box is plotted the binding of the triplet to the ribo-
zome; in this the binding phenylalimine SRNA to the ribo-
zome. As you see in the presence of the appropriate triplet
phenylalimine SRNA binds to ribozomes times plotted against
binding. With the radioactive triplet Dr. Hatfield asked the
question "Is SRNA necessary for the binding of the code word
to the ribozome?" And he finds that it is . Because very
little triplet binds in the absence of SRNA, in the presence
the triplet binds at approximately the same rate as phenyl-
alimine SRNA and approximately the same amount of triplet
binds as phenylalimine SRNA. Thus, the complex may well be

a one-to-one complex on the ribozome.
-13-

I should also point out that major lucine SRNA binds to
ribozome very weakly in response to triplets, and possibly
this type of recognition corresponds to only recognition of
two out of the three phases. Next slide please ...

This shows an experiment with some of Holly's SRNA
plotting concentration of alimine SRNA against binding to
ribozomes. And the dotted line represents hundred per cent
binding, that is, all of the available SRNA in the reaction.
This fraction of SRNA, which Holly sent to us, was estimated
by their laboratory to be greater than 95% pure. And yet
this SRNA fraction recognized quite well three, at least
three of the alimine code-ons ... GCU GCC and GCA. It did
not respond, or responded to a relatively slight extent to
GCG. E-coli SRNA , unfractionated SRNA, responded quite
well to GCG , as a matter of fact, this was the best code-on
--. alimine code-on found as compared to the coli, rather
the yeast, very poor pattern . The GCA GCU and ccc very
little response to GCC ... GCC was an excellent code-on for
alimine with yeast SRNA. Now since this SRNA was of high
purity the results strongly suggest that one molecule of
SRNA can recognize alternately at least three of the four
alimine synonyms. Further, since Holly's laboratory has
recently reported the sequence of alimine SRNA the data
afford some insight into the mechanism of code-on recognition.
Next slide please ...

This is the sequence of alimine SRNA as reported by Holly's
laboratory . The amino acid is linked to the terminal denizine
and this is shown in only one of the possible conformations

that has been suggested by Holly's laboratory. I should point
-12-

This provides very simple and quite sensitive technique
for detecting code-on recognition by SRNA which is not isolated
with amino acids. If Some special function words are not recog-
nized by activating enzymes, not asolated, this would provide
a relatively simple route towards detecting such recognition.
Next slide please ... On this slide is summarized the
work that has gone on in our laboratory with purified SRNA
fractions. This work was done in collaboration with B. P.
Docter at Walter Reed and also Donald Kellogg in our labora-
tory. Tyrazine SRNA both peaks of VERAR PS cognize both UAC
and UAU and this shows the CU pattern in the third position.
A minor peak availing recognizes GUC and GUU . The major
vailing peak, however, recognizes the GU A GUG and to a smaller
extent GUG. All of this work, with one exception, was done
with E-coli SRNA fractions. The E-coli fractions, licine 1
and 2 recognize both licine code-ons. Recently carbon, however,
KaK is reported, just at the Federation meetings a few weeks
ago, that in mammalian liver one species of licine SRNA pref-
erentially recognizes AAG. The other preferentially recog-
nizes AAA. Lucine peak 1A C recognizes CUG , another peak UUG.
The small methianine peak SRNA peak recognizes AUG preferen-
tially, whereas, as I said before, the major peak of methianine
SRNA will accept a formile group and can recognize U UGC UG and
AUG. Triptathane SRNA peak 2 recognizes UGG CGG and to a smaller
aegkeeX extent AGG. Thus, one sees this pattern in the first
position and’ $88h alimine SRNA recognizes GCU GCC and GCA.
The pattern is repeated in the third position. Now this ex-
periment was done with ... this SRNA was obtained from Dr. Robert
Holly with a highly purified fractions of yeast SRNA and I'll

say more about this later.
-14-

that there are several possible single-stranded regions of
interest. This sequence is GToseudoUC has been found in
virtually every SRNA that has been examined. Another inter-
esting sequence is the CGGs surrounded by two dihydrauriditic
acids. And the third is the IGC region which is right in the
middle of a molecule. Next slide please ...

The two sequences of interest are thowe shown here.
The CGG between dihydroU's and the IGC . Now if phase-pairing
--. if these really are the SRNA anti-code-ons,that recognize
the alimine code-ons that are shown here, recognition would
have to be by parallel. pairing between C and G , and the G
would then have to recognize U C and A. If, however, phase
pairing were Watts and Krick hydrogen-bonding anti-parallel
phase pairing C would phase pair with thé G and G with the c
and the inner scene in this position would base pair wxk
alternately with U C or A but not G, which is the pattern
which is observed. Krick has recently proposed a detailed
mechanism xak which would permit hydrogen bonding between
intercine and U C or A. Next slide please ...

And this mechanism simply employs a "wobble" """ A MOVE-
ment of either the SRNA or the messenger RNA on the ribozome .
in the end position. And I think all of the experimental
results are in accord with this type of recognition mechanism
as shown here. The basis in the SRNA anti-code-on is shown
in this column , the basis in the messenger code-on is shown
in this column. The patterns that are found are listed here.

Thus in innercine in SRNA in an end position could recognize
-15-

by alternate base pairing U C or A aG, an end position of
SRNA could recorgnize alternately C or U and A could recognize
UC G and aU could recognize?¥iternate pairing Aor G. We
would also predict that a ribothymadilic acid SRNA would pair
also with A or G , perhaps the interaction with A would be
stronger than a urydilic acid residue , that a pseudoU in

SRNA might recognize alternately A G or U and we have noticed
this pattern with SRNA rather often. And possib1$}€Rat a
dihydrouridylic acid would not base pair so that the interac-
tion with the triplet .. messenger triplet would be/weak
interaction but it's entirely possible that a U or aC in

a terminal position would not greatly inhibit the interaction
so this may be permissible. Also, that a metal group on a
two-prime hydroxyl deribose might result in a weaker interac-—
tion and by permitting greater degree of motion on the ribo-
zome might permit a greater ambiguity. ... a lower specificity.

Next slide please ....

Now the results with the innercine strongly .. and also
the other trace spaces ... rather strongly suggests that ..
actually a great deal of work suggests that SRNA is modified
enzymatically after it is released from DNA templates. And
it seems probable .. that there ... in the cell there exists
a whole spectrum of intermediates. One gets a successive
modification after modification because the level of trace spaces
in SRNA is quite high. Now the consequences of this are
rather simple to visualize. If an A, an admine, for example
in SRNA is de-aminated and converted to an innercine the A
would normally recognize the uradylic acid residue in the

message and the conversion would result in a recognition of
-16-

aUcCor A. Similarly, if a G were converted to an I when we
get this type of inter-conversion , or a C were de-aminated

we would get this type of conversion. The ... it!s too early
really to say ... I think it likely that this type of inter-
conversion occurs and that it has very possibly great biologic
Meaning. Next slide please

There .... really a great deal of work has been done
recently which suggests that ... really a great deal of
work has been done ... which shows that in many cases that
it is possible to modify the specificity of code-on recogni-
tion. I Think that this is biologically a very very impor-
tant point and will have truly profound biologic consequences.
Gorini and Gilbert and Davies at Harvard have shown that
streptomycin will bind to a protein on the 30 s ribozome
the small sub-unit and all the available evidence suggests
that the binding of streptomycin to ribozome may in some
way distort the geography of the code-on recognition site,
to that a greater ambiguaty, a lower specificity may occur
and this may be at least one reason - it may not be the only
reason - one reason which may account for the action of
streptomycin on bacteria. Simply the greater degree of error
occurs in protein synthesis. There may be other mechanisms,
other effects of streptomycin on the cells as well.

Id like to actually list just a few ..pf the recent ...
relatively recent examples of modification of specificity of
code-on recognition that are being studied in various labora-
tories. Streptomycin effect is certainly one, Next slide

please ...
-17-

v Well, before I come to this slide ... I should mention
also the ... some work that ... some very regent work that
we've been doing in collaboration with the Siwilkets at
Princeton . They observed that upon infection of bacterial
cells of C-coli with a virus T2-phage that within one minute
after infection a protein was synthesized by the bacteria
which modified kam a pre-existing lucine SRNA component .
This modification resulted in a shifted movement of the SRNA
on mack columns so it could be purified. We have tested the
code=on recognition of this modified ... this SRNA modifica-
tion which is due to viral infection. And find that it recog-
nizes only poly UG but it doesn't recognize any triplet.
And we have tested all of the UG triplets . Now together
with the modification of the SRNA one finds the cessation of
post-protein synthesis and we don't understand the mechanism
of this ... mechanism of turning off the host protein synthesis
but we think it likely that .. that the enzyme modifies the
lucine SRNA component and this lucine SRNA may in some way
interfere with the initiation of host protein synthesis, but
not a phage synthesis. There's a very subtle way of
subverting the metabolism of the cell so that viral proteins
may be synthesize@ in large amount. And currently this problem
is being worked on .

And here also is some recent study that has been done in
our laboratory by Richard Marshall and Tom Kaske which we
have compared the specificity of code-on recognition in am-
phibian .. with amphibian SRNA .. zenith eslavos , liver

and guinea pig liver SRNA with that of E-coli SRNA . E-coli
-18-

SRNA does not recognize AGG and recognizes CGG with biargine
SRNA only to a very slight extent. Whereas xn both} Smphibian
and mammalian liver we see a very strong response of arginine
SRNA to AGG also to CGG. The alimine SRNA I mentioned
previously with the yeast .. contrast /Pfle yeast and coli patterns
shown here. In both amphibian liver and guinea pig liver
GCC is a very active code-on whereas in the amphibian liver
GCG is a very ... has no activity for alimine SRNA as con-
trasted to coli-SRNA. auayEecognized by isolucine SRNA in
higher forms although we have not detected it in coli. In
all species tested AAA is recognized, whereas AAG has only
slight activity in coli but is a very active code-on in
higher forms. Seriun SRNA UCG xx recognition is variable,
AGU and AGC recognition is variable also as shown here.
3NE ACG is a var iabley$soghati Phere. Now we have found no
differences in the code-on recognition of SRNAs corresponding
to aspartic acid, cystine, glutannic acid, histamine, phenyl-
alimine, proline, tyrazine and also valine which should be on
this slide.

Thus it seems clear that the same sequences correspond
to quibalominic acids throughbut .. from bacteria to mammalian
liver. However, very subtle differences in relative responses
of synonym code-ons are observed. I think that such differences
may, in some cases, play biologic roles. We wonder whether
such differences may be involved in some types of differentia-
tion ... may affect the rate selectively of protein synthesis
in some cases. These are problems I think for the future that
will be worked on within the next year or so and .. we are

very interested in determining the outcome of questions such
-19-

as these. Thank you very much.

Applause

Prof.Devons:
Well as Dr. Rabi said "it's not befitting for a physicist £o
make comments of appreciation of these things." All I can say
is that Dr. Nirenberg has indicated some of the rather breath-
taking speed with which this subject is developing. I am
going to ask Professor Zubay , professor zoology here to
say a few more professional words of appreciation than I can
offer. Prof. Zubay:

Prof.Zubay -

I was hoping Dr. Nirenberg would talk for another 5 minutes
because I was working on some concluding remarks - However,
let me say that I found that this lecture was somewhat more
technical perhaps than most of us have been hearing on these
Monday nights . I am sure that many of you were snowed by

it - as a molecular biologist I assure you everything he said
was correct (laughter) or at least 90% correct. I found it
very exciting and I am sure you noticed how totally immersed
and how exciting he finds his own work. This great crusade
of his began in .. around 1961 when he made the very exciting
announcement in Mostow - I was there at the International
Biochemistry Congress - as to how polyurydelic acids stimu-
lated the incorporation of phenylalimine into a polypeptide
chain. Francis Krick at the time predicted the entire code
would be solved in one year - it has taken a few years longer
than that and the pace, in spite of Krick's prediction , has

been miraculously fast. I think it fair to say that Marshall
-20-

Nirenberg has carried the ball all the way. As a member of
the newly formed Departmnet of Biological Sciences and as a
fellow molecular biologist - I might add, fortunately not a
competitor of Dr. Nirenberg's - let me say that I am deeply
honored to express our collective appreciation for his coming
tonight and for his fine presentation. (Applause)
Prof.DevonsJust a couple of brief announcements. For those who would
like to hear more about this subject, as you will see on the
sheets that have been distributed, Dr. Nirenberg is giving a
talk tomorrow at 10 o'clock in the Watson Laboratories. I
also draw your attention that the date of our next meeting
is Monday , May the Ninth , when Dr. Kendrew from Cambridge
University , will be here to talk about physics, molecular
structure and biological function. That's on Monday, May the

ninth at the usual time. Thank you.