BACKGROUND: During actomyosin interactions, the transduction of energy from ATP hydrolysis to motility seems to occur with the modulation of hydration. Trimethylamine N-oxide (TMAO) perturbs the surface of proteins by altering hydrogen bonding in a manner opposite to that of urea. Hence, we focus on the effects of TMAO on the motility and ATPase activation of actomyosin complexes. METHODS: Actin and heavy meromyosin (HMM) were prepared from rabbit skeletal muscle. Structural changes in HMM were detected using fluorescence and circular dichroism spectroscopy. The sliding velocity of rhodamine-phalloidin-bound actin filaments on HMM was measured using an in vitro motility assay. ATPase activity was measured using a malachite green method. RESULTS: Although TMAO, unlike urea, stabilized the HMM structure, both the sliding velocity and ATPase activity of acto-HMM were considerably decreased with increasing TMAO concentrations from 0-1.0M. Whereas urea-induced decreases in the structural stability of HMM were recovered by TMAO, TMAO further decreased the urea-induced decrease in ATPase activation. Urea and TMAO were found to have counteractive effects on motility at concentrations of 0.6M and 0.2M, respectively. CONCLUSIONS: The excessive stabilization of the HMM structure by TMAO may suppress its activities; however, the counteractive effects of urea and TMAO on actomyosin motor activity is distinct from their effects on HMM stability. GENERAL SIGNIFICANCE: The present results provide insight into not only the water-related properties of proteins, but also the physiological significance of TMAO and urea osmolytes in the muscular proteins of water-stressed animals.
BACKGROUND: During actomyosin interactions, the transduction of energy from ATP hydrolysis to motility seems to occur with the modulation of hydration. Trimethylamine N-oxide (TMAO) perturbs the surface of proteins by altering hydrogen bonding in a manner opposite to that of urea. Hence, we focus on the effects of TMAO on the motility and ATPase activation of actomyosin complexes. METHODS:Actin and heavy meromyosin (HMM) were prepared from rabbit skeletal muscle. Structural changes in HMM were detected using fluorescence and circular dichroism spectroscopy. The sliding velocity of rhodamine-phalloidin-bound actin filaments on HMM was measured using an in vitro motility assay. ATPase activity was measured using a malachite green method. RESULTS: Although TMAO, unlike urea, stabilized the HMM structure, both the sliding velocity and ATPase activity of acto-HMM were considerably decreased with increasing TMAO concentrations from 0-1.0M. Whereas urea-induced decreases in the structural stability of HMM were recovered by TMAO, TMAO further decreased the urea-induced decrease in ATPase activation. Urea and TMAO were found to have counteractive effects on motility at concentrations of 0.6M and 0.2M, respectively. CONCLUSIONS: The excessive stabilization of the HMM structure by TMAO may suppress its activities; however, the counteractive effects of urea and TMAO on actomyosin motor activity is distinct from their effects on HMM stability. GENERAL SIGNIFICANCE: The present results provide insight into not only the water-related properties of proteins, but also the physiological significance of TMAO and urea osmolytes in the muscular proteins of water-stressed animals.
Authors: Paul H Yancey; Mackenzie E Gerringer; Jeffrey C Drazen; Ashley A Rowden; Alan Jamieson Journal: Proc Natl Acad Sci U S A Date: 2014-03-03 Impact factor: 11.205
Authors: Melana Yuzefpolskaya; Bruno Bohn; Paolo C Colombo; Ryan T Demmer; Azka Javaid; Giulio M Mondellini; Lorenzo Braghieri; Alberto Pinsino; Duygu Onat; Barbara Cagliostro; Andrea Kim; Koji Takeda; Yoshifumi Naka; Maryjane Farr; Gabriel T Sayer; Nir Uriel; Renu Nandakumar; Sumit Mohan Journal: Circ Heart Fail Date: 2021-06-15 Impact factor: 10.447