PDBsum entry 3myl

Structural protein

PDB id: 3myl

Contents

Protein chain

744 a.a. *

Ligands

POP

Metals

_MG

Waters ×736

* Residue conservation analysis

PDB id:

3myl

Name:

Structural protein

Title:

Insights into the importance of hydrogen bonding in the gamma- phosphate binding pocket of myosin: structural and functional studies of ser236

Structure:

Myosin-2 heavy chain. Chain: x. Synonym: myosin ii heavy chain. Engineered: yes. Mutation: yes

Source:

Dictyostelium discoideum. Slime mold. Organism_taxid: 44689. Gene: ddb_g0286355, mhca. Expressed in: dictyostelium discoideum. Expression_system_taxid: 44689.

Resolution:

2.00Å R-factor: 0.188 R-free: 0.244

Authors:

J.J.Frye,V.A.Klenchin,C.R.Bagshaw,I.Rayment

Key ref:

J.J.Frye et al. (2010). Insights into the importance of hydrogen bonding in the gamma-phosphate binding pocket of myosin: structural and functional studies of serine 236. Biochemistry, 49, 4897-4907. PubMed id: 20459085

Date:

10-May-10 Release date: 26-May-10

Protein chain

P08799  (MYS2_DICDI) -  Myosin-2 heavy chain from Dictyostelium discoideum

Seq: 2116 a.a.

Struc: 744 a.a.*

* PDB and UniProt seqs differ at 2 residue positions (black crosses)

Biochemistry 49:4897-4907 (2010)

PubMed id: 20459085

Insights into the importance of hydrogen bonding in the gamma-phosphate binding pocket of myosin: structural and functional studies of serine 236.

J.J.Frye, V.A.Klenchin, C.R.Bagshaw, I.Rayment.

ABSTRACT

The active site of myosin contains a group of highly conserved amino acid residues whose roles in nucleotide hydrolysis and energy transduction might appear to be obvious from the initial structural and kinetic analyses but become less clear on deeper investigation. One such residue is Ser236 (Dictyostelium discoideum myosin II numbering) which was proposed to be involved in a hydrogen transfer network during gamma-phosphate hydrolysis of ATP, which would imply a critical function in ATP hydrolysis and motility. The S236A mutant protein shows a comparatively small decrease in hydrolytic activity and motility, and thus this residue does not appear to be essential. To understand better the contribution of Ser236 to the function of myosin, structural and kinetic studies have been performed on the S236A mutant protein. The structures of the D. discoideum motor domain (S1dC) S236A mutant protein in complex with magnesium pyrophosphate, MgAMPPNP, and MgADP.vanadate have been determined. In contrast to the previous structure of wild-type S1dC, the S236A.MgAMPPNP complex crystallized in the closed state. Furthermore, transient-state kinetics showed a 4-fold reduction of the nucleotide release step, suggesting that the mutation stabilizes a closed active site. The structures show that a water molecule approximately adopts the location of the missing hydroxyl of Ser236 in the magnesium pyrophosphate and MgAMPPNP structures. This study suggests that the S236A mutant myosin proceeds via a different structural mechanism than wild-type myosin, where the alternate mechanism is able to maintain near normal transient-state kinetic values.