PDBsum entry 4bql

Contractile protein

PDB id: 4bql

Contents

Protein chains

436 a.a.

Ligands

ADP ×3

Metals

_MG

PDB id:

4bql

Name:

Contractile protein

Title:

Crystal structure of archaeal actin

Structure:

Actin/actin family protein. Chain: a, b, c, d. Synonym: crenactin. Engineered: yes

Source:

Pyrobaculum calidifontis. Organism_taxid: 181486. Strain: jcm11548. Expressed in: escherichia coli. Expression_system_taxid: 469008. Expression_system_variant: rosetta.

Resolution:

3.34Å R-factor: 0.209 R-free: 0.248

Authors:

A.-C.Lindaas,M.Chruszsz,R.Bernander,K.Valegard

Key ref:

A.C.Lindås et al. (2014). Structure of crenactin, an archaeal actin homologue active at 90°C. Acta Crystallogr D Biol Crystallogr, 70, 492-500. PubMed id: 24531483 DOI: 10.1107/S1399004714000935

Date:

31-May-13 Release date: 12-Feb-14

Protein chains

A3MWN5  (CREN1_PYRCJ) -  Crenactin from Pyrobaculum calidifontis (strain DSM 21063 / JCM 11548 / VA1)

Seq: 432 a.a.

Struc: 436 a.a.

Enzyme reactions

• Enzyme class: E.C.3.6.4.- - ?????

DOI no: 10.1107/S1399004714000935

Acta Crystallogr D Biol Crystallogr 70:492-500 (2014)

PubMed id: 24531483

Structure of crenactin, an archaeal actin homologue active at 90°C.

A.C.Lindås, M.Chruszcz, R.Bernander, K.Valegård.

ABSTRACT

The crystal structure of the archaeal actin, crenactin, from the rod-shaped hyperthermophilic (optimal growth at 90°C) crenarchaeon Pyrobaculum calidifontis is reported at 3.35 Å resolution. Despite low amino-acid sequence identity, the three-dimensional structure of the protein monomer is highly similar to those of eukaryotic actin and the bacterial MreB protein. Crenactin-specific features are also evident, as well as elements that are shared between crenactin and eukaryotic actin but are not found in MreB. In the crystal, crenactin monomers form right-handed helices, demonstrating that the protein is capable of forming filament-like structures. Monomer interactions in the helix, as well as interactions between crenactin and ADP in the nucleotide-binding pocket, are resolved at the atomic level and compared with those of actin and MreB. The results provide insights into the structural and functional properties of a heat-stable archaeal actin and contribute to the understanding of the evolution of actin-family proteins in the three domains of life.