3JTD

Calcium-free Scallop Myosin Regulatory Domain with ELC-D19A Point Mutation

Summary for 3JTD

• Entry DOI: 10.2210/pdb3jtd/pdb
• Related: 3JTD
• Descriptor: Myosin heavy chain, striated adductor muscle, Myosin regulatory light chain, striated adductor muscle, Myosin essential light chain, striated adductor muscle, ... (5 entities in total)
• Functional Keywords: regulated myosins, smooth and molluscan muscle, x-ray crystallographic structure, scallop regulatory domain/lever arm, off-state, actin-binding, atp-binding, calmodulin-binding, coiled coil, cytoplasm, motor protein, muscle protein, myosin, nucleotide-binding, thick filament, calcium, contractile protein
• Biological source: Argopecten irradians (Bay scallop); More
• Cellular location: Cytoplasm, myofibril: P24733
• Total number of polymer chains: 3
• Total formula weight: 43305.60

Authors

Himmel, D.M.,Mui, S.,O'Neall-Hennessey, E.,Szent-Gyorgyi, A.,Cohen, C. (deposition date: 2009-09-11, release date: 2009-12-01, Last modification date: 2023-09-06)

Primary citation

Himmel, D.M.,Mui, S.,O'Neall-Hennessey, E.,Szent-Gyorgyi, A.G.,Cohen, C.
The on-off switch in regulated myosins: different triggers but related mechanisms.
J.Mol.Biol., 394:496-505, 2009

PubMed Abstract: In regulated myosin, motor and enzymatic activities are toggled between the on-state and off-state by a switch located on its lever arm domain, here called the regulatory domain (RD). This region consists of a long alpha-helical "heavy chain" stabilized by a "regulatory" light chain (RLC) and an "essential" light chain (ELC). The on-state is activated by phosphorylation of the RLC of vertebrate smooth muscle RD or by direct binding of Ca(2+) to the ELC of molluscan RD. Crystal structures are available only for the molluscan RD. To understand in more detail the pathway between the on-state and the off-state, we have now also determined the crystal structure of a molluscan (scallop) RD in the absence of Ca(2+). Our results indicate that loss of Ca(2+) abolishes most of the interactions between the light chains and may increase the flexibility of the RD heavy chain. We propose that disruption of critical links with the C-lobe of the RLC is the key event initiating the off-state in both smooth muscle myosins and molluscan myosins.

PubMed: 19769984
DOI: 10.1016/j.jmb.2009.09.035

Experimental method

X-RAY DIFFRACTION (2.57 Å)