Biochemical characterization of quinolinic acid phosphoribosyltransferase from Mycobacterium tuberculosis H37Rv and inhibition of its activity by pyrazinamide.
Biochemical characterization of quinolinic acid phosphoribosyltransferase from Mycobacterium tuberculosis H37Rv and inhibition of its activity by pyrazinamide.
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DOI：
10.1371/journal.pone.0100062
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发表时间：
2014
期刊：
影响因子：
3.7
通讯作者：
Mori S
中科院分区：
文献类型：
--
作者：
Kim H;Shibayama K;Rimbara E;Mori S
喹啉酸磷酸核糖基转移酶（QAPRTase, EC 2.4.2.19）是烟酰胺腺嘌呤二核苷酸（NAD）生物合成新途径中的关键酶，也是开发新型抗结核药物的靶标。QAPRTase以喹啉酸（QA）和5-磷酸核糖基-1-焦磷酸（PRPP）为原料，通过磷酸核糖基转移反应和脱羧反应催化合成烟酸单核苷酸。测定了结核分枝杆菌H37Rv QAPRTase （MtQAPRTase）的晶体结构；然而，MtQAPRTase的详细功能分析尚未发表。在此，我们分析了MtQAPRTase的酶活性，并确定了其对抗结核药物吡嗪酰胺（pyrazinamide， PZA）的催化作用。MtQAPRTase活性的最佳温度为60℃，pH为9.2。MtQAPRTase需要二价金属离子，Mg2+存在时其活性最高。动力学分析表明，QA和PRPP的Km值分别为0.08和0.39 mM， QA和PRPP的kcat值分别为0.12和0.14 [s-1]。当可能与QA相互作用的MtQAPRTase的氨基酸残基被丙氨酸残基取代时，催化活性无法检测到。此外，PZA是一种抗结核药物，是QA的结构类似物，可以显著抑制MtQAPRTase的催化活性。PZA的结构可为设计新的MtQAPRTase抑制剂提供依据。这些发现为MtQAPRTase的催化特性提供了新的见解。
Quinolinic acid phosphoribosyltransferase (QAPRTase, EC 2.4.2.19) is a key enzyme in the de novo pathway of nicotinamide adenine dinucleotide (NAD) biosynthesis and a target for the development of new anti-tuberculosis drugs. QAPRTase catalyzes the synthesis of nicotinic acid mononucleotide from quinolinic acid (QA) and 5-phosphoribosyl-1-pyrophosphate (PRPP) through a phosphoribosyl transfer reaction followed by decarboxylation. The crystal structure of QAPRTase from Mycobacterium tuberculosis H37Rv (MtQAPRTase) has been determined; however, a detailed functional analysis of MtQAPRTase has not been published. Here, we analyzed the enzymatic activities of MtQAPRTase and determined the effect on catalysis of the anti-tuberculosis drug pyrazinamide (PZA). The optimum temperature and pH for MtQAPRTase activity were 60°C and pH 9.2. MtQAPRTase required bivalent metal ions and its activity was highest in the presence of Mg2+. Kinetic analyses revealed that the Km values for QA and PRPP were 0.08 and 0.39 mM, respectively, and the kcat values for QA and PRPP were 0.12 and 0.14 [s-1], respectively. When the amino acid residues of MtQAPRTase, which may interact with QA, were substituted with alanine residues, catalytic activity was undetectable. Further, PZA, which is an anti-tuberculosis drug and a structural analog of QA, markedly inhibited the catalytic activity of MtQAPRTase. The structure of PZA may provide the basis for the design of new inhibitors of MtQAPRTase. These findings provide new insights into the catalytic properties of MtQAPRTase.
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影响因子：
2.9
作者：
Di Luccio, Eric;Wilson, David K.
通讯作者：
Wilson, David K.
影响因子：
14.9
作者：
Cer RZ;Mudunuri U;Stephens R;Lebeda FJ
通讯作者：
Lebeda FJ
影响因子：
3.5
作者：
Kim, C;Xuong, NH;Mills, SE
通讯作者：
Mills, SE
DOI：
10.1073/pnas.94.20.10955
发表时间：
1997-09-30
影响因子：
11.1
作者：
Pelicic, V;Jackson, M;Guilhot, C
通讯作者：
Guilhot, C
影响因子：
2.9
作者：
Champagne, Karen S.;Piscitelli, Elise;Francklyn, Christopher S.
通讯作者：
Francklyn, Christopher S.