Role of the 50-kilodalton tryptic peptide of myosin subfragment 1 as a communicating apparatus between the adenosine triphosphatase and actin binding sites

Biochemistry ◽  
1986 ◽  
Vol 25 (8) ◽  
pp. 2101-2109 ◽  
Author(s):  
Toshiaki Hiratsuka
Keyword(s):  
Binding Sites ◽  
Adenosine Triphosphatase ◽  
Tryptic Peptide ◽  
Actin Binding ◽  
Myosin Subfragment ◽  
Myosin Subfragment 1

scholarly journals The Role of Magnesium in Binding of the Nucleotide Polyphosphate Chain to the Active Site of Myosin Subfragment-1

1983 ◽  
Vol 134 (2) ◽  
pp. 197-204 ◽  
Author(s):  
Marcus C. SCHAUB ◽  
John G. WATTERSON ◽  
Klaus LOTH ◽  
Daniela FOLETTA
Keyword(s):  
Active Site ◽  
Myosin Subfragment ◽  
Myosin Subfragment 1

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.

scholarly journals Involvement of caldesmon at the actin-myosin interface

1992 ◽  
Vol 287 (2) ◽  
pp. 633-637 ◽  
Author(s):  
M C Harricane ◽  
E Fabbrizio ◽  
C Arpin ◽  
D Mornet
Keyword(s):  
Ternary Complex ◽  
Actin Binding ◽  
Cross Linking ◽  
Binary Complex ◽  
Binding Region ◽  
Myosin Subfragment ◽  
Myosin Subfragment 1 ◽  
Spacer Arm ◽  
Protein Components ◽  
Chemical Cross Linking

Addition of myosin subfragment 1 (S-1) to the actin-caldesmon binary complex, which forms bundles of actin filaments resulted in the formation of actin/caldesmon-decorated filaments [Harricane, Bonet-Kerrache, Cavadore & Mornet (1991) Eur. J. Biochem. 196, 219-224]. The present data provide further evidence that caldesmon and S-1 compete for a common actin-binding region and demonstrate that a change occurs in the actin-myosin interface induced by caldesmon. S-1 digested by trypsin, which has an actin affinity 100-fold weaker than that of native S-1, was efficiently removed from actin by caldesmon, but not completely dissociated. This particular ternary complex was stabilized by chemical cross-linking with carbodi-imide, which does not have any spacer arm, and revealed contact interfaces between the different protein components. Cross-linking experiments showed that the presence of caldesmon had no effect on stabilization of actin-(20 kDa domain), whereas the actin-(50 kDa domain) covalent association was significantly decreased, to the point of being virtually abolished.

scholarly journals Decoration with myosin subfragment-1 disrupts contacts between microfilaments and the cell membrane in isolated Dictyostelium cortices.

1984 ◽  
Vol 99 (4) ◽  
pp. 1434-1440 ◽  
Author(s):  
H Bennett ◽  
J Condeelis
Keyword(s):  
Cell Membrane ◽  
Binding Sites ◽  
Intestinal Epithelial ◽  
Precise Location ◽  
Contact Sites ◽  
Helical Twist ◽  
Myosin Subfragment ◽  
Structural Nature ◽  
Cell Incubation ◽  
Myosin Subfragment 1

We used isolated cortices from ameboid cells of Dictyostelium discoideum to examine the structural nature of attachments between microfilaments and the cell membrane and to determine the effect of myosin subfragment-1 (S-1) on such contacts. By varying several parameters in our previously described isolation procedure (Condeelis, J., 1979. J. Cell Biol., 80:751-758), we have improved this procedure and have been able to isolate stable cortices. In this paper we identify two types of contact sites between microfilaments and the cell membrane similar to those seen in the brush border of intestinal epithelial cells: (a) an end-on attachment between the barbed end of actin filaments and the cell membrane; and (b) a lateral attachment mediated by rod-shaped bridges measuring approximately 6 X 15 nm. The spacing between bridges averages 36 nm, which suggests that the helical twist of the actin filament influences bridge location. Together these contacts account for an average of approximately 25,000 attachments per cell. Incubation of cortices with concentrations of S-1 sufficient to saturate binding sites on the microfilaments caused disruption of the contacts. This observation was confirmed by quantitative morphometry to show a threefold loss in the number of contact sites following S-1 decoration. These results indicate that S-1 decoration should be used with caution when information about the precise location of microfilaments and their attachment to the membrane is required.

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