文章基本信息

标题：Buried lysine, but not arginine, titrates and alters transmembrane helix tilt
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作者：Nicholas J. Gleason ; Vitaly V. Vostrikov ; Denise V. Greathouse 等
期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2013
卷号：110
期号：5
页码：1692-1695
DOI：10.1073/pnas.1215400110
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：The ionization states of individual amino acid residues of membrane proteins are difficult to decipher or assign directly in the lipid-bilayer membrane environment. We address this issue for lysines and arginines in designed transmembrane helices. For lysines (but not arginines) at two locations within dioleoyl-phosphatidylcholine bilayer membranes, we measure pKa values below 7.0. We find that buried charged lysine, in fashion similar to arginine, will modulate helix orientation to maximize its own access to the aqueous interface or, if occluded by aromatic rings, may cause a transmembrane helix to exit the lipid bilayer. Interestingly, the influence of neutral lysine (vis-a-vis leucine) upon helix orientation also depends upon its aqueous access. Our results suggest that changes in the ionization states of particular residues will regulate membrane protein function and furthermore illustrate the subtle complexity of ionization behavior with respect to the detailed lipid and protein environment.
关键词：GWALP23 ; lysine titration ; solid-state deuterium NMR