High resolution pair-distance distribution function P (r) of protein solutions

A high resolution pair-distance distribution function P (r) of protein molecules has been obtained from the complete solution scattering curve made by combining accurate small-angle and wide-angle x-ray scattering data out to 2.15 Å resolution. Both indirect and direct Fourier transforms exhibit two distinct peaks at 1.4 and 5.1 Å in P (r). X-ray crystallographic data demonstrate that these peaks correspond to two intramolecular distances: the average bond length between C, N, and O atoms and the pitch of an α -helix, respectively. Hence some high resolution aspects of the structure and function of a protein may be investigated in a solution. © 2009 American Institute of Physics.link_to_subscribed_fulltex