3BAT: Crystal Structure Of The N-terminal Region Of The Scallop Myosin Rod, Monoclinic (p21) Form

The N-terminal region of myosin's rod-like subfragment 2 (S2) joins the two heads of this dimeric molecule and is key to its function. Previously, a crystal structure of this predominantly coiled-coil region was determined for a short fragment (51 residues plus a leucine zipper) of the scallop striated muscle myosin isoform. In that study, the N-terminal 10-14 residues were found to be disordered. We have now determined the structure of the same scallop peptide in three additional crystal environments. In each of two of these structures, improved order has allowed visualization of the entire N-terminus in one chain of the dimeric peptide. We have also compared the melting temperatures of this scallop S2 peptide with those of analogous peptides from three other isoforms. Taken together, these experiments, along with examination of sequences, point to a diminished stability of the N-terminal region of S2 in regulated myosins, compared with those myosins whose regulation is thin filament linked. It seems plain that this isoform-specific instability promotes the off-state conformation of the heads in regulated myosins. We also discuss how myosin isoforms with varied thermal stabilities share the basic capacity to transmit force efficiently in order to produce contraction in their on states.
PDB ID: 3BATDownload
MMDB ID: 61719
PDB Deposition Date: 2007/11/8
Updated in MMDB: 2017/11
Experimental Method:
x-ray diffraction
Resolution: 2.3  Å
Similar Structures:
Biological Unit for 3BAT: dimeric; determined by author and by software (PISA)
Molecular Components in 3BAT
Label Count Molecule
Proteins (2 molecules)
Myosin Heavy Chain, Striated Muscle/general Control Protein Gcn4(Gene symbol: GCN4)
Molecule annotation
* Click molecule labels to explore molecular sequence information.

Citing MMDB