Electron density modeling and reconstruction of infinite periodic minimal surfaces (IPMS) based phases in lipid-water systems. II. Reconstruction of D surface based phases |
| |
Authors: | PE Harper SM Gruner RNAH Lewis RN McElhaney |
| |
Institution: | (1) Department of Physics, Joseph Henry Laboratories, Jadwin Hall, Princeton University, Princeton NJ 08544, USA, US;(2) Department of Biochemistry, The University of Alberta, Edmonton, Alberta, Canada T6G 2H7, CA |
| |
Abstract: | This is the second of two papers dealing with the structure of lipid-water phases based on Infinite Periodic Minimal Surfaces
(IPMS). The first paper describes mathematical modeling of such phases. In this paper, a new reconstruction method, called
the methyl trough search, is described and used to solve the structures based on powder pattern X-ray diffraction data. Structures
are derived for both a single chain lipid-water system (mono-olein) and a diacyl phospholipid-water system (2-2 methyl butyl
16:0 phosphatidylcholine). The methyl trough search uses the low electron density of the lipid methyl tails to determine the
correct phasing for the electron density reconstruction. The data are consistent with a structure based on the IPMS D surface.
The results are compared to other methods used to solve the mono-olein structure; the structure of the diacyl lipid has never
before been solved. We discuss the subtleties involved in reconstruction of D surface based phases and the substantial artifacts
that arise in low-resolution reconstructions of hydrocarbon lipids lacking heavy-atom sites.
Received 15 January 1999 and Received in final form 20 October 1999 |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|