Publication
Title
Archaeal protoglobin structure indicates new ligand diffusion paths and modulation of haem-reactivity
Author
Abstract
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 C2Aa strictly anaerobic methanogenic Archaeais, 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 Å 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 O2, 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 O2/CO binding to the haem that favours O2 ligation and anticooperativity in ligand binding. Both properties are exceptional within the Hb superfamily.
Language
English
Source (journal)
EMBO reports. - Oxford, 2000, currens
Publication
Oxford : 2008
ISSN
1469-221X
1469-3178 [online]
Volume/pages
9:2(2008), p. 157-163
ISI
000253778400012
Full text (Publishers DOI)
UAntwerpen
Faculty/Department
Research group
Publication type
Subject
Affiliation
Publications with a UAntwerp address
External links
Web of Science
Record
Identification
Creation 07.04.2009
Last edited 30.03.2017
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