Sandbox Reserved 930: Difference between revisions
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==Introduction== | ==Introduction== | ||
[[Image:Actin myosin anim.gif|400px|left|thumb| Figure 1. The movement of myosin motor domain on actin filament]] | [[Image:Actin myosin anim.gif|400px|left|thumb| Figure 1. The movement of myosin motor domain on actin filament (San Diego State University College of Sciences, reference no. xxx)]] | ||
[[Image:myosin.png|450px|right|thumb| Figure 2. The contractile cycle of the myosin head]] | [[Image:myosin.png|450px|right|thumb| Figure 2. The contractile cycle of the myosin head (Krans 2010, reference number xxx).]] | ||
In the striated muscle the actin and myosin proteins form ordered basic units called sarcomeres. Muscle contraction is achieved by the mechanical sliding of myosin filament (thick filament) along the actin filament (thin filament), Fig. 1. The major constituent of the myosin filament is myosin, a motor protein responsible for converting chemical energy to mechanical movement. In the presence of Ca<sup>2+</sup> and Mg<sup>2+</sup>, myosin is able to cyclically bind ATP and hydrolyse it to ADP + P<sub>i</sub> , thus triggering subsequent myosin-actin detachment, reattachment and power stroke, the so called contractile reaction (Fig.2). | In the striated muscle the actin and myosin proteins form ordered basic units called sarcomeres. Muscle contraction is achieved by the mechanical sliding of myosin filament (thick filament) along the actin filament (thin filament), Fig. 1. The major constituent of the myosin filament is myosin, a motor protein responsible for converting chemical energy to mechanical movement. In the presence of Ca<sup>2+</sup> and Mg<sup>2+</sup>, myosin is able to cyclically bind ATP and hydrolyse it to ADP + P<sub>i</sub> , thus triggering subsequent myosin-actin detachment, reattachment and power stroke, the so called contractile reaction (Fig.2). | ||
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==The subdomains of the motor domain== | ==The subdomains of the motor domain== | ||
[[Image:SUBDOMAINS.gif|400px|right|thumb|Figure 3. The subdomains on myosin S1 unit]] | [[Image:SUBDOMAINS.gif|400px|right|thumb|Figure 3. The subdomains on myosin S1 unit (Houdusse 2000)]] | ||
The MD of the scallop S1 unit is most frequently described as consisting of four subdomains: the converter, the N-terminal subdomain, and the upper and lower 50-kDa subdomains <ref>PMID: 10338210</ref>. They are linked together by three single-stranded joints termed the switch II (residues IIe-461 to Asn-470), the relay (residues Asn-489 to Asp-519), and SH1 helix (residues Cys-693 to Phe-707)(Fig. 3) <ref>PMID: 11016966</ref>. | The MD of the scallop S1 unit is most frequently described as consisting of four subdomains: the converter, the N-terminal subdomain, and the upper and lower 50-kDa subdomains <ref>PMID: 10338210</ref>. They are linked together by three single-stranded joints termed the switch II (residues IIe-461 to Asn-470), the relay (residues Asn-489 to Asp-519), and SH1 helix (residues Cys-693 to Phe-707)(Fig. 3) <ref>PMID: 11016966</ref>. | ||
