TY - JOUR

T1 - The primary cause of muscle disfunction associated with substitutions E240K and R244G in tropomyosin is aberrant behavior of tropomyosin and response of actin and myosin during ATPase cycle

AU - Симонян, Армен Оганесович

AU - Sirenko, Vladimir V.

AU - Karpicheva, O.E.

AU - Robaszkiewicz, K.

AU - Śliwinska, Malgorzata

AU - Moraczewska, J.

AU - Крутецкая, Зоя Иринарховна

AU - Borovikov, Yurii S.

N1 - Funding Information: The work was supported by the Russian Science Foundation (Grant Number 17-14-01224 ) and the statutory funds of Kazimierz Wielki University .

PY - 2018/4/15

Y1 - 2018/4/15

N2 - Using the polarized photometry technique we have studied the effects of two amino acid replacements, E240K and R244G, in tropomyosin (Tpm1.1) on the position of Tpm1.1 on troponin-free actin filaments and the spatial arrangement of actin monomers and myosin heads at various mimicked stages of the ATPase cycle in the ghost muscle fibres. E240 and R244 are located in the C-terminal, seventh actin-binding period, in f and b positions of the coiled-coil heptapeptide repeat. Actin, Tpm1.1, and myosin subfragment-1 (S1) were fluorescently labeled: 1.5-IAEDANS was attached to actin and S1, 5-IAF was bound to Tpm1.1. The labeled proteins were incorporated in the ghost muscle fibres and changes in polarized fluorescence during the ATPase cycle have been measured. It was found that during the ATPase cycle both mutant tropomyosins occupied a position close to the inner domain of actin. The relative amount of the myosin heads in the strongly-bound conformations and of the switched on actin monomers increased at mimicking different stages of the ATPase cycle. This might be one of the reasons for muscle dysfunction in congenital fibre type disproportion caused by the substitutions E240K and R244G in tropomyosin.

AB - Using the polarized photometry technique we have studied the effects of two amino acid replacements, E240K and R244G, in tropomyosin (Tpm1.1) on the position of Tpm1.1 on troponin-free actin filaments and the spatial arrangement of actin monomers and myosin heads at various mimicked stages of the ATPase cycle in the ghost muscle fibres. E240 and R244 are located in the C-terminal, seventh actin-binding period, in f and b positions of the coiled-coil heptapeptide repeat. Actin, Tpm1.1, and myosin subfragment-1 (S1) were fluorescently labeled: 1.5-IAEDANS was attached to actin and S1, 5-IAF was bound to Tpm1.1. The labeled proteins were incorporated in the ghost muscle fibres and changes in polarized fluorescence during the ATPase cycle have been measured. It was found that during the ATPase cycle both mutant tropomyosins occupied a position close to the inner domain of actin. The relative amount of the myosin heads in the strongly-bound conformations and of the switched on actin monomers increased at mimicking different stages of the ATPase cycle. This might be one of the reasons for muscle dysfunction in congenital fibre type disproportion caused by the substitutions E240K and R244G in tropomyosin.

KW - Congenital myopathies

KW - F-actin

KW - Fluorescence polarization

KW - Ghost muscle fibres

KW - Myosin

KW - Tropomyosin

KW - Troponin

KW - F-ACTIN

KW - COMPLEX

KW - GESTALT-BINDING

KW - THIN FILAMENT ACTIVATION

KW - RABBIT SKELETAL-MUSCLE

KW - MODEL

KW - FIBER

KW - CONFORMATIONAL-CHANGES

KW - CONTRACTION

KW - MUTATIONS

UR - http://www.scopus.com/inward/record.url?scp=85043605854&partnerID=8YFLogxK

UR - http://www.mendeley.com/research/primary-cause-muscle-disfunction-associated-substitutions-e240k-r244g-tropomyosin-aberrant-behavior

U2 - 10.1016/j.abb.2018.03.002

DO - 10.1016/j.abb.2018.03.002

M3 - Article

VL - 644

SP - 17

EP - 28

JO - Archives of Biochemistry and Biophysics

JF - Archives of Biochemistry and Biophysics

SN - 0003-9861

ER -