Publications by authors named "L Reshetnikova"
Purification, crystallization and preliminary X-ray crystallographic analysis of squid heavy meromyosin.
Acta Crystallogr Sect F Struct Biol Cryst Commun
March 2013
All muscle-based movement is dependent upon carefully choreographed interactions between the two major muscle components, myosin and actin. Regulation of vertebrate smooth and molluscan muscle contraction is myosin based (both are in the myosin II class), and requires the double-headed form of myosin. Removal of Ca2+ from these muscles promotes a relatively compact conformation of the myosin dimer, which inhibits its interaction with actin.
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- The crystal structure of a phosphorylated smooth-muscle myosin light chain domain (LCD) from sea scallops was determined, focusing on a specific regulatory light chain.
- Arg(16), an arginine unique to this isoform, plays a crucial role by stabilizing the phosphorylation site through interactions with both unphosphorylated and phosphorylated states.
- Despite these interactions, the overall conformation of the LCD remains unchanged upon phosphorylation, suggesting it may not serve as a regulatory on-switch for muscle contraction in scallop catch muscle.
Article Synopsis
- The crystal structure of a myosin light chain domain from sea scallop muscle was determined at 2.3-Å resolution, revealing important conformational changes during muscle contraction.
- The structure shows two different conformations around the heavy chain hook and regulatory light chain helix D, leading to a significant difference in the lever arm length (10 Å).
- The research suggests that certain hinges in the structure may contribute to muscle flexibility and the transition between active ("on") and inactive ("off") states of myosin, with implications for understanding contractile mechanisms.
Article Synopsis
- The N-terminal region of myosin's subfragment 2 (S2) is crucial for the function of its dimeric structure.
- Previous studies established that this region is mostly disordered, but new crystal structures show enhanced order, allowing visualization of the entire N-terminus.
- Comparisons of thermal stability across different myosin isoforms suggest that the instability in regulated myosins favors an off-state conformation, impacting their ability to efficiently transmit force during muscle contraction.
Unlike processive cellular motors such as myosin V, whose structure has recently been determined in a "rigor-like" conformation, myosin II from contracting muscle filaments necessarily spends most of its time detached from actin. By using squid and sea scallop sources, however, we have now obtained similar rigor-like atomic structures for muscle myosin heads (S1). The significance of the hallmark closed actin-binding cleft in these crystal structures is supported here by actin/S1-binding studies.
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