Differential scanning calorimetric study of the complexes of modified myosin subfragment 1 with ADP and vanadate or beryllium fluoride

Nina L. Golitsina, Andrey A. Bobkov, Irina V. Dedova, Dmitrii A. Pavlov, Olga P. Nikolaeva, Victor N. Orlov, Dmitrii I. Levitsky*

*Corresponding author for this work

Research output: Contribution to journalArticle

17 Citations (Scopus)

Abstract

The effects of various modifications of rabbit skeletal myosin subfragment 1 on thermal denaturation of subfragment 1 in ternary complexes with Mg-ADP and orthovanadate (V(i)) or beryllium fluoride (BeFx) have been studied by differential scanning calorimetry. It has been shown that specific modifications of SH1 group of Cys-707 by different sulfhydryl reagents, trinitrophenylation of Lys-83, and reductive methylation of lysine residues promote the decomposition of the S1·ADP·Vi complex and change the character of structural transitions of the subfragment 1 molecule induced by the formation of this complex, but they have much less or no influence on subfragment 1 thermal stability in the S1·ADP·BeFx complex. Thus, the differential scanning calorimetric studies on modified subfragment 1 preparations reveal a significant difference between S1·ADP·Vi and S1·ADP·BeFx complexes. It is suggested that S1·ADP·Vi and S1·ADP·BeFx complexes represent structural analogues of different transition states of the ATPase cycle, namely the intermediate states S1*·ADP·Pi and S1*·ATP, respectively. It is also proposed that during formation of the S1·ADP·Vi complex the region containing both Cys-707 and Lys-83 plays an important role in the spread of conformational changes from the active site of subfragment 1 ATPase throughout the structure of the entire subfragment 3 molecule. In such a case, the effects of reductive methylation of lysine residues on the subfragment 1 structure in the S1·ADP·Vi complex are related to the modification of Lys-83.

Original languageEnglish
Pages (from-to)475-485
Number of pages11
JournalJournal of Muscle Research and Cell Motility
Volume17
Issue number4
DOIs
Publication statusPublished - Aug 1996
Externally publishedYes

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