Structural enzymology and inhibition of the bi-functional folate pathway enzyme HPPK-DHPS from the biowarfare agent Francisella tularensis.
Structural enzymology and inhibition of the bi-functional folate pathway enzyme HPPK-DHPS from the biowarfare agent Francisella tularensis.
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DOI：
10.1111/febs.12896
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发表时间：
2014-09
期刊：
影响因子：
--
通讯作者：
Ji X
中科院分区：
文献类型：
--
作者：
Shaw GX;Li Y;Shi G;Wu Y;Cherry S;Needle D;Zhang D;Tropea JE;Waugh DS;Yan H;Ji X
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. While Pemble and coworkers determined the structure of FtHPPK-DHPS, they were unable to measure the kinetic parameters of the enzyme (PloS one 5, e14165). 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 1/2.6×105 that of Escherichia coli DHPS. Sequence and structural analyses suggest that HP-26 is an excellent lead for developing tularemia therapeutics 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 10 F. tularensis genomes indicated that the bacterium contains a single FtHPPK-DHPS. The marginal DHPS activity and the singular 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 mutation may make the marginal DHPS activity unable to support the growth of F. tularensis.
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影响因子：
14.9
作者：
Cer RZ;Mudunuri U;Stephens R;Lebeda FJ
通讯作者：
Lebeda FJ
DOI：
10.1107/s0907444904019158
发表时间：
2004-12-01
影响因子：
2.2
作者：
Emsley, P;Cowtan, K
通讯作者：
Cowtan, K
影响因子：
7.3
作者：
Hevener, Kirk E.;Yun, Mi-Kyung;Lee, Richard E.
通讯作者：
Lee, Richard E.
影响因子：
5.6
作者：
Hennig, M;Dale, GE;Oefner, C
通讯作者：
Oefner, C
影响因子：
5.7
作者：
Babaoglu, K;Qi, JJ;White, SW
通讯作者：
White, SW