1gv3
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THE 2.0 ANGSTROM RESOLUTION STRUCTURE OF THE CATALYTIC PORTION OF A CYANOBACTERIAL MEMBRANE-BOUND MANGANESE SUPEROXIDE DISMUTASE
OverviewOverview
Cyanobacteria are shown to be unique in containing membrane-bound, manganese superoxide dismutases (MnSOD). They are homodimeric type 2, membrane proteins that protect this phototrophic organism against, oxidative stress. We have determined, for the first time, the 2.0A, resolution structure of the catalytic portion of the MnSOD from the, filamentous cyanobacterium Anabaena PCC 7120. Within each subunit, both, the N-terminal helical hairpin (His94 and His145) and the C-terminal, alpha/beta domain (His232 and Asp228) contribute ligands to the catalytic, manganese site. Together with a water or hydroxide ion (OH(x)) a, five-coordinated trigonal bipyramidal geometry is formed, with OH(x) and, His90 forming the axial ligands and manganese shifted out of the, equatorial plane in the direction of OH(x). The ligands including OH(x), are tightly constrained by hydrogen bonding with surrounding residues, either from the same monomer (Tyr98, Asn144, Trp194, Gln213, Val229, Trp230) or from the neighbouring subunit (Glu231, Tyr235). This underlines, the important role of the symmetric dimeric structure of MnSODs in, contributing elements to both the active site and the substrate funnel., The Mn cdots, three dots, centered Mn distance (18.4A) is bridged by the, hydrogen-bonded His232 of one monomer with Glu231 of the other monomer. A, detailed discussion of the structure, a comparison with known structures, of soluble MnSODs as well as a model of the cyanobacterial membrane-bound, MnSOD is presented.
About this StructureAbout this Structure
1GV3 is a Single protein structure of sequence from Anabaena sp. with MN as ligand. Known structural/functional Site: . Full crystallographic information is available from OCA.
ReferenceReference
The 2.0A resolution structure of the catalytic portion of a cyanobacterial membrane-bound manganese superoxide dismutase., Atzenhofer W, Regelsberger G, Jacob U, Peschek G, Furtmuller P, Huber R, Obinger C, J Mol Biol. 2002 Aug 16;321(3):479-89. PMID:12162960
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