scholarly journals Correlation between calponin and myosin subfragment 1 binding to F-actin and ATPase inhibition

1997 ◽  
Vol 321 (2) ◽  
pp. 519-523 ◽  
Author(s):  
Pawel T. SZYMANSKI ◽  
Zenon GRABAREK ◽  
Terence TAO
Keyword(s):  
Troponin I ◽  
Sequence Similarity ◽  
Actin Binding ◽  
Amino Acid Sequence Similarity ◽  
Smooth Muscle Contractility ◽  
Skeletal Muscle Myosin ◽  
Myosin Subfragment ◽  
Myosin Subfragment 1 ◽  
Muscle Myosin ◽  
Atpase Inhibition

Calponin is a thin-filament-associated protein that has been implicated in the regulation of smooth-muscle contractility. It binds to F-actin and inhibits the MgATPase activity of actomyosin. In the present work we have examined the effect of recombinant chicken gizzard α-calponin (RαCaP) on the binding of rabbit skeletal-muscle myosin subfragment 1 (S1) to F-actin and on the inhibition of its actin-activated MgATPase. We have found that binding of one RαCaP molecule to every three to four actin monomers is sufficient for maximal inhibition of actoŐS1 ATPase. At this RαCaP/actin ratio RαCaP does not interfere with S1 binding to F-actin. At higher concentrations, RαCaP displaces S1 from F-actin and a 1:1 RαCaPŐactin monomer complex is formed. RαCaP is also able to displace troponin I from its complex with F-actin which may reflect the amino acid sequence similarity between RαCaP and troponin I in their actin-binding regions.

Skeletal muscle myosin subfragment 1 dimers

1997 ◽  
Vol 65 (1) ◽  
pp. 85-90 ◽  
Author(s):  
Karen Claire ◽  
Robert Pecora ◽  
Stefan Highsmith
Keyword(s):  
Skeletal Muscle ◽  
Skeletal Muscle Myosin ◽  
Myosin Subfragment ◽  
Myosin Subfragment 1 ◽  
Muscle Myosin

scholarly journals Characterization of an actin-myosin head interface in the 40–113 region of actin using specific antibodies as probes

1990 ◽  
Vol 271 (2) ◽  
pp. 407-413 ◽  
Author(s):  
J P Labbé ◽  
C Méjean ◽  
Y Benyamin ◽  
C Roustan
Keyword(s):  
Myosin Head ◽  
Interface Model ◽  
Filamentous Actin ◽  
Skeletal Muscle Myosin ◽  
Myosin Subfragment ◽  
Myosin Subfragment 1 ◽  
Myosin Interaction ◽  
Muscle Myosin ◽  
Covalent Complex

Evidence for the participation of the 1-7 and 18-28 N-terminal sequences of actin at different steps of actin-myosin interaction process is well documented in the literature. Cross-linking of the rigor complex between filamentous actin and skeletal-muscle myosin subfragment 1 was accomplished by the carboxy-group-directed zero-length protein cross-linker, 1-ethyl-3-[3-(dimethylamino)propyl]carbodi-imide. After chaotropic depolymerization and thrombin digestion, which cleaves only actin, the covalent complex with Mr 100,000 was characterized by PAGE. The linkage was identified as being between myosin subfragment 1 (S-1) heavy chain and actin-(1-28)-peptide. The purified complex retained in toto its ability to combine reversibly with fresh filamentous actin, but showed a decrease in the Vmax. of actin-dependent Mg2(+)-ATPase. By using e.l.i.s.a., S-1 was observed to bind to coated monomeric actin or its 1-226 N-terminal peptide. This interaction strongly interfered with the binding of antibodies directed against the 95-113 actin sequence. Moreover, S-1 was able to bind with coated purified actin-(40-113)-peptide. Finally, antibodies directed against the 18-28 and 95-113 actin sequence, which strongly interfered with S1 binding, were unable to compete with each other. These results suggest that two topologically independent regions are involved in the actin-myosin interface: one located in the conserved 18-28 sequence and the other near residues 95-113, including the variable residue at position 89. Other experiments support the ‘multisite interface model’, where the two actin sites could modulate each other during S-1 interaction.

scholarly journals Interaction of skeletal-muscle myosin subfragment-1 with the actin-(338-348) peptide.

1994 ◽  
Vol 299 (3) ◽  
pp. 875-879 ◽  
Author(s):  
J P Labbé ◽  
S Lelievre ◽  
M Boyer ◽  
Y Benyamin
Keyword(s):  
Skeletal Muscle ◽  
Binding Site ◽  
Antigenic Site ◽  
Filamentous Actin ◽  
Apparent Dissociation Constant ◽  
Skeletal Muscle Myosin ◽  
Myosin Subfragment ◽  
Myosin Subfragment 1 ◽  
Order Of Magnitude ◽  
Muscle Myosin

The data presented here confirm and provide further experimental evidence that rabbit skeletal-muscle myosin subfragment-1 (S-1) binds to the postulated actin-(338-348) hydrophobic segment [Kabsch, Mannherz, Suck, Pai and Holmes (1990) Nature (London) 347, 37-44] with high affinity in the absence and presence of MgATP. The apparent dissociation constant of the S-1 interaction (5.5 x 10(-7) M) with the actin-(338-348) peptide was of the same order of magnitude as that of the actin-(18-28) binding site (2 x 10(-6) M). In similar conditions, fragmented (27 kDa-50 kDa-20 kDa) S-1 also bound to the peptide. Antibodies directed to the vicinal sequence 348-358 were rapidly eliminated from actin by S-1 interaction and weakened S-1 binding to monomeric or filamentous actin. The antigenic site (348-358) is located very close to the C-terminal S-1-binding site (360-369) and encompasses some residues (Leu-349 and Phe-352) included in the hydrophobic S-1-binding region [Schröder, Manstein, Jahn, Holden, Rayment, Holmes and Spudich (1993) Nature (London) 364, 171-174]. It was observed that anti-[actin-(348-358)] antibodies were also unable to decrease actomyosin ATPase activity, in contrast with previous results obtained with anti-[actin-(18-28)] antibodies [Adams and Reisler (1993) Biochemistry 32, 5051-5056]. The hydrophobic actin-(338-348) peptide used in considerable excess was unable to perturb acto-S-1 and S-1 activities in contrast with results obtained with the N-terminal actin peptide [Kôgler, Moir, Trayer and Ruegg (1991) FEBS Lett. 294, 31-34].

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