Fifty years ago, the great un solved problem of biology seemed to be the structure of proteins.

Bill Astbury, a physicist and X-ray crystallographer working for the Wool Research Association in Leeds (United Kingdom), discovered that the fibrous protein keratin, found in wool, horn, nails and muscle, gave a common X-ray diffraction pattern consisting of just two reflections, a meridionalone at 5.1 Å and an equatorial one at 9.8 Å.

Astbury called this the a-keratin pattern. When these fibers were stretched under steam, a new pattern appeared with a meridional reflection at 3.4 Å and two equatorial ones at 4.5 and 9.7 Å. Astbury called this the b-keratin pattern. He concluded that it arose from the regular repeat of amino acid residues along straight polypeptide chains, whereas the chains in a-keratin must be folded or coiled such that several amino acid residues form a pattern repeating every 5.1 Å along...

Interested in reading more?

Become a Member of

Receive full access to digital editions of The Scientist, as well as TS Digest, feature stories, more than 35 years of archives, and much more!
Already a member?