Structural and Functional Properties of Kappa Tropomyosin

Kopylova, G.V.; Kochurova, A.M.; Yampolskaya, D.S.; Nefedova, V.V.; Tsaturyan, A.K.; Koubassova, N.A.; Kleymenov, S.Y.; Levitsky, D.I.; Bershitsky, S.Y.; Matyushenko, A.M.; Shchepkin, D.V.

Авторы: Kopylova Galina V., Kochurova Anastasia M., Yampolskaya Daria S., Nefedova Victoria V., Tsaturyan Andrey K., Koubassova Natalia A., Kleymenov Sergey Y., Levitsky Dmitrii I., Bershitsky Sergey Y., Matyushenko Alexander M., Shchepkin Daniil V.
Журнал: International Journal of Molecular Sciences
Том: 24
Номер: 9
Год издания: 2023
Издательство: MDPI
Местоположение издательства: Basel, Switzerland
Первая страница: 8340
DOI: 10.3390/ijms24098340
Аннотация: n the myocardium, the TPM1 gene expresses two isoforms of tropomyosin (Tpm), alpha (αTpm; Tpm 1.1) and kappa (κTpm; Tpm 1.2). κTpm is the result of alternative splicing of the TPM1 gene. We studied the structural features of κTpm and its regulatory function in the atrial and ventricular myocardium using an in vitro motility assay. We tested the possibility of Tpm heterodimer formation from α- and κ-chains. Our result shows that the formation of ακTpm heterodimer is thermodynamically favorable, and in the myocardium, κTpm most likely exists as ακTpm heterodimer. Using circular dichroism, we compared the thermal unfolding of ααTpm, ακTpm, and κκTpm. κκTpm had the lowest stability, while the ακTpm was more stable than ααTpm. The differential scanning calorimetry results indicated that the thermal stability of the N-terminal part of κκTpm is much lower than that of ααTpm. The affinity of ααTpm and κκTpm to F-actin did not differ, and ακTpm interacted with F-actin significantly worse. The troponin T1 fragment enhanced the κκTpm and ακTpm affinity to F-actin. κκTpm differently affected the calcium regulation of the interaction of pig and rat ventricular myosin with the thin filament. With rat myosin, calcium sensitivity of thin filaments containing κκTpm was significantly lower than that with ααTpm and with pig myosin, and the sensitivity did not differ. Thin filaments containing κκTpm and ακTpm were better activated by pig atrial myosin than those containing ααTpm
Добавил в систему: Кубасова Наталия Алексеевна

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Structural and Functional Properties of Kappa Tropomyosinстатья

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