3I5H: The Crystal Structure Of Rigor Like Squid Myosin S1 In The Absence Of Nucleotide

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. These structures reveal how different duty ratios, and hence cellular functions, of the myosin isoforms may be accounted for, in part, on the basis of detailed differences in interdomain contacts. Moreover, the rigor-like position of switch II turns out to be unique for myosin V. The overall arrangements of subdomains in the motor are relatively conserved in each of the known contractile states, and we explore qualitatively the energetics of these states.
PDB ID: 3I5HDownload
MMDB ID: 75697
PDB Deposition Date: 2009/7/5
Updated in MMDB: 2011/10
Experimental Method:
x-ray diffraction
Resolution: 3.4  Å
Source Organism:
Doryteuthis pealeii
Similar Structures:
Biological Unit for 3I5H: trimeric; determined by author and by software (PISA)
Molecular Components in 3I5H
Label Count Molecule
Proteins (3 molecules)
Myosin Heavy Chain Isoform a
Molecule annotation
Myosin Regulatory Light Chain Lc-2, Mantle Muscle
Molecule annotation
Myosin Catalytic Light Chain Lc-1, Mantle Muscle
Molecule annotation
Chemical (1 molecule)
* Click molecule labels to explore molecular sequence information.

Citing MMDB