1zhg
From Proteopedia
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Crystal structure of Beta-Hydroxyacyl-Acyl Carrier Protein Dehydratase (FabZ) from Plasmodium falciparum
Overview
The crystal structure of beta-hydroxyacyl acyl carrier protein dehydratase, of Plasmodium falciparum (PfFabZ) has been determined at a resolution of, 2.4 A. PfFabZ has been found to exist as a homodimer (d-PfFabZ) in the, crystals of the present study in contrast to the reported hexameric form, (h-PfFabZ) which is a trimer of dimers crystallized in a different, condition. The catalytic sites of this enzyme are located in deep narrow, tunnel-shaped pockets formed at the dimer interface. A histidine residue, from one subunit of the dimer and a glutamate residue from the other, subunit lining the tunnel form the catalytic dyad in the reported crystal, structures. While the position of glutamate remains unaltered in the, crystal structure of d-PfFabZ compared to that in h-PfFabZ, the histidine, residue takes up an entirely different conformation and moves away from, the tunnel leading to a His-Phe cis-trans peptide flip at the histidine, residue. In addition, a loop in the vicinity has been observed to undergo, a similar flip at a Tyr-Pro peptide bond. These alterations not only, prevent the formation of a hexamer but also distort the active site, geometry resulting in a dimeric form of FabZ that is incapable of, substrate binding. The dimeric state and an altered catalytic site, architecture make d-PfFabZ distinctly different from the FabZ structures, described so far. Dynamic light scattering and size exclusion, chromatographic studies clearly indicate a pH-related switching of the, dimers to active hexamers.
About this Structure
1ZHG is a Single protein structure of sequence from Plasmodium falciparum. Full crystallographic information is available from OCA.
Reference
Crystal structure of dimeric FabZ of Plasmodium falciparum reveals conformational switching to active hexamers by peptide flips., Swarnamukhi PL, Sharma SK, Bajaj P, Surolia N, Surolia A, Suguna K, FEBS Lett. 2006 May 15;580(11):2653-60. Epub 2006 Apr 21. PMID:16643907
Page seeded by OCA on Sun Nov 25 04:53:13 2007
