3TYD image
Entry Detail
PDB ID:
3TYD
Keywords:
Title:
Dihydropteroate Synthase in complex with PPi and DHP+
Biological Source:
Source Organism:
Host Organism:
PDB Version:
Deposition Date:
2011-09-24
Release Date:
2012-03-14
Method Details:
Experimental Method:
Resolution:
2.50 Å
R-Value Free:
0.27
R-Value Work:
0.22
R-Value Observed:
0.22
Space Group:
P 62 2 2
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:Dihydropteroate synthase
Chain IDs:A, B
Chain Length:297
Number of Molecules:2
Biological Source:Bacillus anthracis
Primary Citation
Catalysis and sulfa drug resistance in dihydropteroate synthase.
Science 335 1110 1114 (2012)
PMID: 22383850 DOI: 10.1126/science.1214641

Abstact

The sulfonamide antibiotics inhibit dihydropteroate synthase (DHPS), a key enzyme in the folate pathway of bacteria and primitive eukaryotes. However, resistance mutations have severely compromised the usefulness of these drugs. We report structural, computational, and mutagenesis studies on the catalytic and resistance mechanisms of DHPS. By performing the enzyme-catalyzed reaction in crystalline DHPS, we have structurally characterized key intermediates along the reaction pathway. Results support an S(N)1 reaction mechanism via formation of a novel cationic pterin intermediate. We also show that two conserved loops generate a substructure during catalysis that creates a specific binding pocket for p-aminobenzoic acid, one of the two DHPS substrates. This substructure, together with the pterin-binding pocket, explains the roles of the conserved active-site residues and reveals how sulfonamide resistance arises.

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