2vee

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spinqualitylabelsall models 2vee, resolution 2.60Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

STRUCTURE OF PROTOGLOBIN FROM METHANOSARCINA ACETIVORANS C2A

Overview

The structural adaptability of the globin fold has been highlighted by the recent discovery of the 2-on-2 haemoglobins, of neuroglobin and cytoglobin. Protoglobin from Methanosarcina acetivorans C2A-a strictly anaerobic methanogenic Archaea-is, to the best of our knowledge, the latest entry adding new variability and functional complexity to the haemoglobin (Hb) superfamily. Here, we report the 1.3 A crystal structure of oxygenated M. acetivorans protoglobin, together with the first insight into its ligand-binding properties. We show that, contrary to all known globins, protoglobin-specific loops and an amino-terminal extension completely bury the haem within the protein matrix. Access of O(2), CO and NO to the haem is granted by the protoglobin-specific apolar tunnels reaching the haem distal site from locations at the B/G and B/E helix interfaces. Functionally, M. acetivorans dimeric protoglobin shows a selectivity ratio for O(2)/CO binding to the haem that favours O(2) ligation and anticooperativity in ligand binding. Both properties are exceptional within the Hb superfamily.

About this Structure

2VEE is a Single protein structure of sequence from Methanosarcina acetivorans with as ligand. Known structural/functional Sites: , , , , , , and . Full crystallographic information is available from OCA.

Reference

Archaeal protoglobin structure indicates new ligand diffusion paths and modulation of haem-reactivity., Nardini M, Pesce A, Thijs L, Saito JA, Dewilde S, Alam M, Ascenzi P, Coletta M, Ciaccio C, Moens L, Bolognesi M, EMBO Rep. 2008 Feb;9(2):157-63. Epub 2008 Jan 11. PMID:18188182

Page seeded by OCA on Thu Feb 21 18:55:11 2008