UBIVERSITY OF CASKBRIDGE     DEPARTM!ET OF PHYSICS

Free School Lane,
    Car&ridge.

21st January ly.53.

I Dr. David Narker,

Polytechnic Institute of Brooklyn,
The Protein Stpucture Project,
55 Johnson Street, 4th Floop,
Brooklyn 1, New York,





Dear I?r, Napker,

      Thank you fop your letter of 7th January,   3 have heard
from Wycd&ff who seems to think there will be little difficult-v
in gettirig our vt.s3 interview rather earlier,   I shall write'to
the Eltlfriassy 3s soopz 3s I have cle3ped Michael with the Divorce Court,
Naturally 1 did not expect the
vfsa,                  Cravelling mone`y before we got the
    1 willlet you know later on how things c3.n most easily
be 3rZranged.

                                                                      
        As to the apartment
and go higher,           1 suggest you relax first the.price,
      say up to $Ll2cj, B  If there nre still
difficulties 1 think we should not worry too much about the
ne9.ghbouqhood.  We certainly don't want to buy furniture, md we
really need three bedrooms if this is at all possible, It is really
very kind of you to do this fop us.

      T was very pleased to hear 3bout your various forms of
ri.boauclease,  %%e work in Bepml's laboratory has suffered, in my
v,iew, due to their excessive corzcentr5tton ofi one form,   Have you
been able to derive any inf'orrE3tion. from studying the changes du,e
to different salt concentl?,~tlons?

lines,   As ted-kepntin, L think Paulin& model is o
   but ppobs.b$,y far qy reasons,             g, the right
indicated, not 14) as I suggested,   A tilt of about 9  is certainly
                         The simple formula 5& #a~( is

correct for 3 tilted helix, but not for a coidhelix, a& csn be
either from the &act theory which I have worked out, .or from    seen

symmetry considerations,  I have written more fully about this to
   alld snid he might show you the let-ter.

-* A

1 ~3s interested to hear about Dr, Luzzati, both from
               -.

am morn ltjemtz.   Some time ago X looked into the question of
putting the haemoglobin data on 3n a'bsolute scale,   The question
is complimtcd by doubtsi 3s to how mmy of the atoms in the cpyst31
are opdgred, and by the fact that the observed data only goes out
to 2.8n +  P. considered the iMegra1  Se&u


This c:>n be predicted , given sufficient rcso'ution, from the.
chemicxl formula - since one knows the radial distance of all
neighbours within about 2.7A" of all the atoms irrespcctivc of
how the molecule folds up.   One h3s to calculate the tempewture
Pwtor from the data, a.nd it is difficult to do this unambiguously
unless the wcor ded intensities go a good w3y out.   fi came to the
oonclusion that one should algays plut the intensities 0.;1 an absolute
scale by direct measurement.   Theory might then be 3ble to show
what frC~Ci;ion of the 3toms is disordered.

     As to the A-h&lia in globular proteins, I don't think
anybody here nom believes -that haemoglobin consists mainly of .long
straight ~>arallel rods,  since such a model is clearly incompa6able
with the Ei&terson.   The key question is whether it consis.t$ m3inly
of 4-helices, not necessary plarallel,   This -is pleusible, since it
xiay be n-gide x~p of four non-parcllel myoglobin-type units, and moreover
gackin;: consiii.er3tion.s show th3tod-helices of the s3ate sense proi:;ably
prefer to close--I::3ck at about 20 from pawllel, for the reasons given
in my Nature letter,

1 have just drafted 3
j-n aml wound ,thc 1CAo
el.   I use the relsti

,paper in whirh I s
region is crudel.y
0X-l

ht>t the  tot31
,erable w ith

c?_FJter c?-j-gy971,?:
comer::e.nce. -- 8 heuvy artWicia1 tr:mr!erature factor to' ensure
          This approach c3.n be gei:erE?lised by rei:eoted
diffzretxtiation,  and I sh311 be interested to see if Luzzati .is
work.ir,g. on similar lines.

      I don't think we shall be 3bl.e to come to zwg dofinite
conclusion here unti3. Kendrcx L3s the 3 dixezsioi?al. Patterson of
n~oglobit?;, which we believe to be distiwtly more "TOddy" th3n
haemogL5bf.n.

Wth best wishes,

Yours sincerely,

Francis Crick,