1t9h

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spinqualitylabelsall models 1t9h, resolution 1.60Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

The crystal structure of YloQ, a circularly permuted GTPase.

Overview

yloQ is one of 11 essential genes in Bacillus subtilis with unknown roles, in the physiology of the cell. It encodes a polypeptide of 298 residues, with motifs characteristic of GTPases. As a contribution to elucidating, its indispensable cellular function, we have solved the crystal structure, of YloQ to 1.6 A spacing, revealing a three-domain organisation. At the, heart of the molecule is the putative GTPase domain, which exhibits a, classical alpha/beta nucleotide-binding fold with a topology very similar, to that of Ras and Era. However, as anticipated from the order in which, the conserved G protein motifs appear in the sequence, the GTPase domain, fold in YloQ is circularly permuted with respect to the classical GTPases., The nucleotide-binding pocket in YloQ is unoccupied, and analysis of the, phosphate-binding (P) loop indicates that conformational changes in this, region would be needed to accommodate GTP. The GTPase domain is flanked at, its N terminus by a beta-barrel domain with an, oligonucleotide/oligosaccharide-binding (OB) fold, and at its C terminus, by an alpha-helical domain containing a coordinated zinc ion. This, combination of protein modules is unique to YloQ and its orthologues., Sequence comparisons reveal a clustering of conserved basic and aromatic, residues on one face of the OB domain, perhaps pointing to a role for YloQ, in nucleic acid binding. The zinc ion in the alpha-helical domain is, coordinated by three cysteine residues and a histidine residue in a novel, ligand organisation. The juxtaposition of the switch I and switch II, regions of the G domain and the OB and zinc-binding domains suggests that, chemical events at the GTPase active site may be transduced into relative, movements of these domains. The pattern of conserved residues and, electrostatic surface potential calculations suggest that the OB and/or, Zn-binding domains participate in nucleic acid binding consistent with a, possible role for YloQ at some stage during mRNA translation.

About this Structure

1T9H is a Single protein structure of sequence from Bacillus subtilis with IUM, ZN, CA and ACT as ligands. Full crystallographic information is available from OCA.

Reference

The crystal structure of YloQ, a circularly permuted GTPase essential for Bacillus subtilis viability., Levdikov VM, Blagova EV, Brannigan JA, Cladiere L, Antson AA, Isupov MN, Seror SJ, Wilkinson AJ, J Mol Biol. 2004 Jul 16;340(4):767-82. PMID:15223319

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