3E0W: Crystal Structure Of Pyruvate Kinase From Leishmania Mexicana

Citation:
Abstract
We report X-ray structures of pyruvate kinase from Leishmania mexicana (LmPYK) that are trapped in different conformations. These, together with the previously reported structure of LmPYK in its inactive (T-state) conformation, allow comparisons of three different conformers of the same species of pyruvate kinase (PYK). Four new site point mutants showing the effects of side-chain alteration at subunit interfaces are also enzymatically characterised. The LmPYK tetramer crystals grown with ammonium sulphate as precipitant adopt an active-like conformation, with sulphate ions at the active and effector sites. The sulphates occupy positions similar to those of the phosphates of ligands bound to active (R-state) and constitutively active (nonallosteric) PYKs from several species, and provide insight into the structural roles of the phosphates of the substrates and effectors. Crystal soaking in sulphate-free buffers was found to induce major conformational changes in the tetramer. In particular, the unwinding of the Aalpha6' helix and the inward hinge movement of the B domain are coupled with a significant widening (4 A) of the tetramer caused by lateral movement of the C domains. The two new LmPYK structures and the activity studies of site point mutations described in this article are consistent with a developing picture of allosteric activity in which localised changes in protein flexibility govern the distribution of conformer families adopted by the tetramer in its active and inactive states.
PDB ID: 3E0WDownload
MMDB ID: 66215
PDB Deposition Date: 2008/8/1
Updated in MMDB: 2008/11
Experimental Method:
x-ray diffraction
Resolution: 3.1  Å
Source Organism:
Similar Structures:
Biological Unit for 3E0W: tetrameric; determined by author and by software (PISA)
Molecular Components in 3E0W
Label Count Molecule
Proteins (4 molecules)
4
Pyruvate Kinase
Molecule annotation
* Click molecule labels to explore molecular sequence information.

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