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Nucleotide-induced movements of essential light chain-1 in myosin subfragment 1 as studied by fluorescence resonance energy transfer (FRETтезисы доклада
- Авторы: Daria Logvinova, Alexander Matyushenko, Olga Nikolaeva, Dmitrii Levitsky
- Сборник: Abstracts of 46th European Muscle Conference
- Тезисы
- Год издания: 2017
- Место издания: Potsdam
- Первая страница: 35
- Последняя страница: 35
- Аннотация: Rabbit fast skeletal muscle myosin has two isoforms of the essential light chain (ELC), called LC1 and LC3. The LC1 differs from LC3 by the presence of N-terminal extension of 41 residues containing seven pairs of Ala-Pro repeats, which form an elongated structure, and two pairs of Lys residues near the N-terminus. When isolated myosin head (myosin subfragment 1, S1) binds to F-actin, these Lys residues may interact with the C-terminus of actin thus forming an additional actin-binding site on S1. Here we applied fluorescence resonance energy transfer to measure for the first time the distances between Cys374 on actin and different sites on the Nterminal extension of LC1 associated with S1. Cys374 of actin was labeled with 1,5- IAEDANS as a donor, and S1 was reconstituted with various recombinant LC1 mutants which were fluorescently labeled with 5-IAF (acceptor) at different positions in their N-terminal extension and then introduced into the S1 regulatory domain. At physiological ionic strength (120–150 mM NaCl) and S1:actin molar ration equal to 1:3 (i.e. under conditions when the LC1 N-terminal extension interacts with actin), the following distances were calculated between Cys374 on actin and different sites on the N-terminal extension of LC1: > 6 nm to Cys41, 4–5 nm to Cys15 located among AlaPro repeats, and 3–4 nm to Cys residues located near Lys residues at the N-terminus. At higher ionic strength (above 300 mM NaCl) and S1:actin molar ration equal to 1:1 (i.e. under conditions preventing interaction of the LC1 N-terminus with actin) all these distances significantly increased. These results are consistent with the previously proposed concepts and also reveal new interesting details of the molecular mechanism of the interaction of LC1 N-terminal extension with actin, which may play an important role in actin-myosin interaction during muscle contraction. This work was supported by RFBR (grant 15-04-03037).
- Добавил в систему: Логвинова Дарья Сергеевна