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The effect of D137L and G126R mutations in alpha-tropomyosin on the position and flexibility during the ATPase cycleтезисы доклада
Информация о цитировании статьи получена из
Web of Science
Дата последнего поиска статьи во внешних источниках: 7 сентября 2017 г.
- Авторы: Rysev N.A., Matyushenko A.M., Artemova N.V., Levitsky D.I., Borovikov Y.S.
- Сборник: Journal of Muscle Research and Cell Motility
- Серия: Abstracts of 43rd European muscle conference, Salzburg, Austria
- Том: 36
- Тезисы
- Год издания: 2015
- Место издания: Springer Salzburg, Austria
- Первая страница: 105
- Последняя страница: 105
- DOI: 10.1007/s10974-015-9407-3
- Аннотация: The effect of G126R and D137L substitutions within skeletal atropomyosin (TM) on spatial arrangement of TM and actin subunits in troponin-free actin filaments of ghost muscle fibres were studied at different stages of the ATPase cycle. The wild-type recombinant TM, G126R, D137L and G126R/D137L mutant TMs were labelled with 5-IAF at Cys36 residue introduced into TM by C190A/S36C mutation. F-actin was labelled with FITC-phalloidin. The ghost fibres containing the labelled proteins were studied by polarized fluorimetry technique. It is believed that TM shift to the centre of the filament during the ATPase cycle correlates with a clockwise rotation of actin subunits around the filament axis. These changes in conformation switch the actin subunits from the off to the on state, imparting them the ability to promote phosphate release from the myosin active centre, and thereby to activate the ATPase reaction. Consistent with this view we observed that, during the ATPase cycle, the control TM moved from the filament periphery to the centre and actin subunits switched on. As compared to the control TM, the mutant TMs were found to be shifted further to the periphery of actin filament at mimicking the weak-binding stages of actomyosin interaction, which resulted in a pronounced increase in the number of the switched off actin subunits. At mimicking the strong-binding stages, the mutant TMs moved further to the centre of the filament and the amount of the switched on actin subunits extremely increased. The effect reached its maximum with the G126R/D137L mutant. The abnormal pattern of mutant TM movement during the ATPase cycle may be responsible for the earlier observed increase in Ca2+-sensitivity of actin-myosin interaction and maximal sliding velocity of actin filaments in the in vitro motility assay induced by D137L and G126R substitutions in TM. This work was supported by RFBR (Grants 14-04-00454-a, 12-04-00411-a, 13-04-40099-H).
- Добавил в систему: Боровиков Юрий Сергеевич