 |
PDBsum entry 2vee
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Transport protein
|
PDB id
|
|
|
|
2vee
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
References listed in PDB file
|
|
|
Key reference
|
|
|
Title
|
|
Archaeal protoglobin structure indicates new ligand diffusion paths and modulation of haem-Reactivity.
|
|
|
Authors
|
|
M.Nardini,
A.Pesce,
L.Thijs,
J.A.Saito,
S.Dewilde,
M.Alam,
P.Ascenzi,
M.Coletta,
C.Ciaccio,
L.Moens,
M.Bolognesi.
|
|
|
Ref.
|
|
Embo Rep, 2008,
9,
157-163.
|
|
|
PubMed id
|
|
|
|
|
|
|
|
|
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 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.
|
|
|
|
|
|
|
