4PZV

Crystal structure of Francisella tularensis HPPK-DHPS in complex with bisubstrate analog HPPK inhibitor J1D

Summary for 4PZV

• Entry DOI: 10.2210/pdb4pzv/pdb
• Related: 4F7V
• Descriptor: 2-amino-4-hydroxy-6-hydroxymethyldihydropteridine pyrophosphokinase/dihydropteroate synthase, 5'-{[2-({N-[(2-amino-7,7-dimethyl-4-oxo-3,4,7,8-tetrahydropteridin-6-yl)carbonyl]glycyl}amino)ethyl]sulfonyl}-5'-deoxyadenosine, 1,2-ETHANEDIOL, ... (4 entities in total)
• Functional Keywords: ferredoxin-like fold; tim barrel fold, transferase, atp binding, phosphorylation
• Biological source: Francisella tularensis subsp. tularensis
• Total number of polymer chains: 1
• Total formula weight: 49382.92

Authors

Shaw, G.X.,Shi, G.,Ji, X. (deposition date: 2014-03-31, release date: 2014-07-16, Last modification date: 2023-09-20)

Primary citation

Shaw, G.X.,Li, Y.,Shi, G.,Wu, Y.,Cherry, S.,Needle, D.,Zhang, D.,Tropea, J.E.,Waugh, D.S.,Yan, H.,Ji, X.
Structural enzymology and inhibition of the bi-functional folate pathway enzyme HPPK-DHPS from the biowarfare agent Francisella tularensis.
Febs J., 281:4123-4137, 2014

PubMed Abstract: Two valid targets for antibiotic development, 6-hydroxymethyl-7,8-dihydropterin pyrophosphokinase (HPPK) and dihydropteroate synthase (DHPS), catalyze consecutive reactions in folate biosynthesis. In Francisella tularensis (Ft), these two activities are contained in a single protein, FtHPPK-DHPS. Although Pemble et al. (PLoS One 5, e14165) determined the structure of FtHPPK-DHPS, they were unable to measure the kinetic parameters of the enzyme. In this study, we elucidated the binding and inhibitory activities of two HPPK inhibitors (HP-18 and HP-26) against FtHPPK-DHPS, determined the structure of FtHPPK-DHPS in complex with HP-26, and measured the kinetic parameters for the dual enzymatic activities of FtHPPK-DHPS. The biochemical analyses showed that HP-18 and HP-26 have significant isozyme selectivity, and that FtHPPK-DHPS is unique in that the catalytic efficiency of its DHPS activity is only 1/260,000 of that of Escherichia coli DHPS. Sequence and structural analyses suggest that HP-26 is an excellent lead for developing therapeutic agents for tularemia, and that the very low DHPS activity is due, at least in part, to the lack of a key residue that interacts with the substrate p-aminobenzoic acid (pABA). A BLAST search of the genomes of ten F. tularensis strains indicated that the bacterium contains a single FtHPPK-DHPS. The marginal DHPS activity and the single copy existence of FtHPPK-DHPS in F. tularensis make this bacterium more vulnerable to DHPS inhibitors. Current sulfa drugs are ineffective against tularemia; new inhibitors targeting the unique pABA-binding pocket may be effective and less subject to resistance because any mutations introducing resistance may make the marginal DHPS activity unable to support the growth of F. tularensis.

PubMed: 24975935
DOI: 10.1111/febs.12896

Experimental method

X-RAY DIFFRACTION (1.704 Å)