Dissertation in Draft: Chapter IX

Date:
1953
Reference:
PP/CRI/F/1/9
Catalogue details

Licence: In copyright

Credit: Dissertation in Draft: Chapter IX. Source: Wellcome Collection.

    1/11
    Csì SiVir Por», U*. - CnLj - ^ i I ¡J - ->1' rvc Htv*- ^.T fr-ïùuvy ¡Mro-ih^nJ^ f>pe- The simple structures described so far - the t-wis=^^x and tkr¿¿ -1 Yru^J. topjt the - may he the basis of long thin molecules, such as tropomyosin, which are only two or three polypeptide chains thick. The X-ray diagram to he expected from a loose array of such molecules would have the hroad characteristics already described, that is, a diffuse oL diagram. One is unlikely to detect very long spacings, unless the orientation and packing were particularly good, since the only strong reflexions to show a long axial periodicity are the near-equatorials, and these would probably be merged with the true equatorials. We should expect a diffuse meridional arc in the 5 R region, with an emphasis on the meridian at about 5.15 K. The equatorials reflections near 10 R would be expected to be rather diffuse, and perhaps at a rather greater average spacing than usual, due to the difficulties of packing. This is a fair description of the X-ray results of Astbury, Reed and Spark (19U8$ for stretched films -20-