PDBsum entry 1lkx

Contractile protein

PDB id: 1lkx

Contents

Protein chains

650 a.a. *

Ligands

VO4-ADP ×4

Metals

_MG ×4

Waters ×64

* Residue conservation analysis

PDB id:

1lkx

Name:

Contractile protein

Title:

Motor domain of myoe, a class-i myosin

Structure:

Myosin ie heavy chain. Chain: a, b, c, d. Fragment: motor domain. Engineered: yes

Source:

Dictyostelium discoideum. Organism_taxid: 44689. Expressed in: dictyostelium discoideum. Expression_system_taxid: 44689.

Resolution:

3.00Å R-factor: 0.228 R-free: 0.273

Authors:

M.Kollmar,U.Durrwang,W.Kliche,D.J.Manstein,F.J.Kull

Key ref:

M.Kollmar et al. (2002). Crystal structure of the motor domain of a class-I myosin. EMBO J, 21, 2517-2525. PubMed id: 12032065 DOI: 10.1093/emboj/21.11.2517

Date:

26-Apr-02 Release date: 26-Jun-02

Protein chains

Q03479  (MYOE_DICDI) -  Myosin IE heavy chain from Dictyostelium discoideum

Seq: 1005 a.a.

Struc: 650 a.a.*

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

Enzyme reactions

• Enzyme class: E.C.?

DOI no: 10.1093/emboj/21.11.2517

EMBO J 21:2517-2525 (2002)

PubMed id: 12032065

Crystal structure of the motor domain of a class-I myosin.

M.Kollmar, U.Dürrwang, W.Kliche, D.J.Manstein, F.J.Kull.

ABSTRACT

The crystal structure of the motor domain of Dictyostelium discoideum myosin-IE, a monomeric unconventional myosin, was determined. The crystallographic asymmetric unit contains four independently resolved molecules, highlighting regions that undergo large conformational changes. Differences are particularly pronounced in the actin binding region and the converter domain. The changes in position of the converter domain reflect movements both parallel to and perpendicular to the actin axis. The orientation of the converter domain is approximately 30 degrees further up than in other myosin structures, indicating that MyoE can produce a larger power stroke by rotating its lever arm through a larger angle. The role of extended loops near the actin-binding site is discussed in the context of cellular localization. The core regions of the motor domain are similar, and the structure reveals how that core is stabilized in the absence of an N-terminal SH3-like domain.

Selected figure(s)

Figure 3.
Figure 3 Contacts between the relay region, converter domain and lever arm helix allow these structural elements to move together. (A) The relay region and SH1 helix of MyoE are shown in cyan. In MyoE and other class-I myosins, there is a hydrogen bond between Thr418 in the relay helix and Asn618 from the SH1 helix. (B) Close-up view of this region, viewed along the relay helix. The kink forms at Thr418. (C) Highly conserved residues form a hydrophobic core, and polar residues further stabilize the link via conserved hydrogen bonds (dashed lines). This core interaction is further supported by a small, hydrophobic, highly conserved extension into the converter formed by residues Tyr630 and Val677 (DdTyr699 and DdIle744). At the tip of the relay loop (cyan), conserved Glu429 (DdGlu497) forms hydrogen bonds to residue Thr675 of the converter domain (brown) (DdThr742; at this position there is always a threonine or a serine) and to the backbone nitrogen atoms of converter residues Lys674 and Lys676. (D) Hydrophobic interactions between the lever arm helix (cyan) and core domain (white). All class-I myosins contain an aromatic residue at the positions of Tyr69 and/or Tyr71 (red) in close contact with the conserved Phe686 (red) in the lever arm helix. Either a glycine or an alanine is found at the equivalent position to Phe686 in class-II myosins.

Figure 4.
Figure 4 A model of chicken skeletal muscle myosin motor core (white), converter domain and lever arm (yellow) in the near-rigor state attached to the actin filament (dark gray). Dictyostelium myosin-II in complex with ADP-BeF[3] with a modeled extended lever arm in the 'up' or transition state position is shown in red. The MyoE converter domain and modeled extended lever arm (cyan) is in an 30° higher position.

The above figures are reprinted from an Open Access publication published by Macmillan Publishers Ltd: EMBO J (2002, 21, 2517-2525) copyright 2002.

Figures were selected by an automated process.