2veb | pdb_00002veb
HIGH RESOLUTION STRUCTURE OF PROTOGLOBIN FROM METHANOSARCINA ACETIVORANS C2A
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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
2VEB is a Single protein structure of sequence from Methanosarcina acetivorans with PO4, HEM, OXY and GOL as ligands. Known structural/functional Sites: AC1, AC2, AC3, AC4 and AC5. 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 Jan 11;. PMID:18188182
Page seeded by OCA on Wed Jan 23 10:56:44 2008
