کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1253925 | 1496373 | 2006 | 18 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Lipid conformation in crystalline bilayers and in crystals of transmembrane proteins
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی (عمومی)
پیش نمایش صفحه اول مقاله
![عکس صفحه اول مقاله: Lipid conformation in crystalline bilayers and in crystals of transmembrane proteins Lipid conformation in crystalline bilayers and in crystals of transmembrane proteins](/preview/png/1253925.png)
چکیده انگلیسی
Dihedral torsion angles evaluated for the phospholipid molecules resolved in the X-ray structures of transmembrane proteins in crystals are compared with those of phospholipids in bilayer crystals, and with the phospholipid conformations in fluid membranes. Conformations of the lipid glycerol backbone in protein crystals are not restricted to the gauche C1-C2 rotamers found invariably in phospholipid bilayer crystals. Lipid headgroup conformations in protein crystals also do not conform solely to the bent-down conformation, with gauche-gauche configuration of the phospho-diester, that is characteristic of phospholipid bilayer membranes. This suggests that the lipids that are resolved in crystals of membrane proteins are not representative of the entire lipid-protein interface. Much of the chain configurational disorder of the membrane-bound lipids in crystals arises from energetically disallowed skew conformations. This indicates a configurational heterogeneity in the lipids at a single binding site: eclipsed conformations occur also in some glycerol backbone torsion angles and C-C torsion angles in the lipid headgroups. Stereochemical violations in the protein-bound lipids are evidenced by one-third of the ester carboxyl groups in non-planar configurations, and certain of the carboxyls in the cis configuration. Some of the lipid structures in protein crystals have the incorrect enantiomeric configuration of the glycerol backbone, and many of the branched methyl groups in structures of the phytanyl chains associated with bacteriorhodopsin crystals are in the incorrect S-configuration.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Chemistry and Physics of Lipids - Volume 141, Issues 1â2, June 2006, Pages 48-65
Journal: Chemistry and Physics of Lipids - Volume 141, Issues 1â2, June 2006, Pages 48-65
نویسندگان
Derek Marsh, Tibor Páli,