文章基本信息

标题：Conformation and packing of unsaturated chains in crystals of cholesteryl nervonate at 123 K.
本地全文：下载
作者：P Sawzik ; B M Craven
期刊名称：JLR Papers In Press
印刷版ISSN：0022-2275
电子版ISSN：1539-7262
出版年度：1984
卷号：25
期号：8
页码：851-856
语种：English
出版社：American Society for Biochemistry and Molecular Biology
摘要：At 123 K, cholesterol cis-15-tetracosenoate (cholesteryl nervonate, C51H90O2) is monoclinic, space group P2(1) with a = 12.948(5), b = 8.805(5), c = 42.98(5) A, beta = 105.93(3) degrees, [lambda(CuK alpha) = 1.5418 A], having two independent molecules (A) and (B) in the unit cell. The crystal structure at 123 K has been determined from 6329 reflections with sin theta/lambda less than 0.54 A-1, of which 1990 gave I greater than 2 sigma(I). Structure refinement by Fourier methods and block diagonal least squares gave R = 0.232 for all reflections, R = 0.135 for those with I greater than 2 sigma(I). The crystal structure consists of layers in which there is close packing of cholesteryl groups and the proximal segments of the ester chains. This layer structure occurs also in cholesteryl palmitoleate and the alkanoate esters C9 through C12. Because the nervonate chains are longer, they become aligned in the interface region between layers, but without a regular subcell structure being established. The nervonate (A)-chain is almost extended, while the (B)-chain has two bends, one in the saturated region. Both chains have complex dislocations at the cis-double bond.