The interaction of troponin-I with the N-terminal region of actin.
The interaction between troponin-I and actin that underlies thin-filament regulation in striated muscle has been studied using proton magnetic resonance spectroscopy. A restricted portion of skeletal muscle troponin-I (residues 96-116) has previously been shown to be capable of inhibiting the MgATPase activity of actomyosin in a manner enhanced by tropomyosin [Syska et al. (1976) Biochem. J. 153, 375-387]. On the basis of homologous spectral effects for signals of specific groups observed in different complexes formed using the native proteins and a variety of defined peptides, it is concluded that the segment of troponin-I which has inhibitory activity interacts with the N-terminal region of actin. The surface of contact of the inhibitory segment of troponin-I with actin involves two regions of the N-terminal of actin. These are located between residues 1-7 and 19-44. The data are discussed in the context of a structural mechanism for the inhibition of myosin ATPase activation.
Levine
B A
BA
Inorganic Chemistry Laboratory, University of Oxford, England.
Moir
A J
AJ
Perry
S V
SV
D000199:Actins / Q000378:metabolism*; D000251:Adenosine Triphosphatases / Q000037:antagonists & inhibitors; D000818:Animals; D001665:Binding Sites; D004789:Enzyme Activation; D009682:Magnetic Resonance Spectroscopy; D009132:Muscles / Q000201:enzymology; D011485:Protein Binding; D011817:Rabbits; D013499:Surface Properties; D014336:Troponin / Q000378:metabolism*; D019210:Troponin I
D000199:Actins; D014336:Troponin; D019210:Troponin I; D000251:Adenosine Triphosphatases