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：1991
卷号：88
期号：21
页码：9748-9750
DOI：10.1073/pnas.88.21.9748
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：It appears that small movements (detected hitherto only by fluorescence resonance energy transfer measurements and crosslinking studies) in a region of the myosin S-1 particle may mediate chemomechanical energy transduction in the contractile system. Here we find under conditions of high precision at 10 degrees C and 20 degrees C that ATP binding to S-1 causes small (0.4%) changes in CD signal, delta epsilon 222, as do temperature changes in the regime below 16 degrees C. ATP binding perturbs tryptophan residues that we now think are in the mobile region, and we find here that temperature affects tryptophan fluorescence in much the same way that it affects the CD signal, so we believe that the CD signal reports transduction-related movements in S-1. If S-1 is exposed to the range 16-30 degrees C, CD signal falls with temperature; ATP counteracts this fall. Analysis of vacuum-UV CD spectra yields 42% alpha-helix, 9% antiparallel beta-sheet, 7% parallel beta-sheet, 14% beta-turns, and 29% other structures.
