期刊
JOURNAL OF MOLECULAR BIOLOGY
卷 394, 期 3, 页码 535-543出版社
ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD
DOI: 10.1016/j.jmb.2009.09.041
关键词
phosphoglycerate mutase; Leishmania; parasite; glycolysis; crystal structure
资金
- MRC
- European Commission [ICA4-CT-2001-10075]
- Royal Thai Government Scholarship, Ministry of Science and Technology, Thailand
- Wellcome Trust
- BBSRC
- Medical Research Council [G0600014] Funding Source: researchfish
- MRC [G0600014] Funding Source: UKRI
The structures of Leishmania mexicana cofactor-independent phosphoglycerate mutase (Lm iPGAM) crystallised with the substrate 3-phosphoglycerate at high and low cobalt concentrations have been solved at 2.00- and 1.90-angstrom resolutions. Both structures are very similar and the active site contains both 3-phosphoglycerate and 2-phosphoglycerate at equal occupancies (50%). Lm iPGAM co-crystallised with the product 2-phosphoglycerate yields the same structure. Two Co2+ are coordinated within the active site with different geometries and affinities. The cobalt at the M1 site has a distorted octahedral geometry and is present at 100% occupancy. The M2-site Co2+ binds with distorted tetrahedral geometry, with only partial occupancy, and coordinates with Ser75, the residue involved in phosphotransfer. When the M2 site is occupied, the side chain of Ser75 adopts a position that is unfavourable for catalysis, indicating that this site may not be occupied under physiological conditions and that catalysis may occur via a one-metal mechanism. The geometry of the M2 site suggests that it is possible for Ser75 to be activated for phosphotransfer by H-bonding to nearby residues rather than by metal coordination. The 16 active-site residues of Lm iPGAM are conserved in the Mn-dependent iPGAM from Bacillus stearothermophilus (33% overall sequence identity). However, Lm iPGAM has an inserted tyrosine (Tyr210) that causes the M2 site to diminish in size, consistent with its reduced metal affinity. Tyr210 is present in trypanosomatid and plant iPGAMs, but not in the enzymes from other organisms, indicating that there are two subclasses of iPGAMs. Crown Copyright (C) 2009 Published by Elsevier Ltd. All rights reserved.
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