Glycolytic and Non-glycolytic Functions of Mycobacterium tuberculosis Fructose-1,6-bisphosphate Aldolase, an Essential Enzyme Produced by Replicating and Non-replicating Bacilli
Glycolytic and Non-glycolytic Functions of Mycobacterium tuberculosis Fructose-1,6-bisphosphate Aldolase, an Essential Enzyme Produced by Replicating and Non-replicating Bacilli
复制标题
DOI：
10.1074/jbc.m111.259440
复制
发表时间：
2011-11-18
影响因子：
4.8
通讯作者：
Jackson, Mary
中科院分区：
文献类型：
--
作者：
de la Paz Santangelo, Maria;Gest, Petra M.;Jackson, Mary
寻找抗结核药物的活性对持久性杆菌导致我们的兴趣，金属依赖性II类果糖-1，6-二磷酸醛缩酶（FBA-tb），一个关键酶的同源性缺乏哺乳动物细胞。在fba-tb位点的敲除实验表明，该基因是结核分枝杆菌生长所必需的，在含葡萄糖的培养基上的eigenetic基板。表面标记和酶活性测定表明，该酶被输出到M.结核杆菌，并在各种无菌生长条件下产生，包括氧气消耗，因此由非复制型杆菌产生。重要的是，FBA-tb也在受感染的豚鼠和小鼠的肺中体内产生。FBA-tb结合人纤溶酶（原），并保护FBA-tb结合的纤溶酶不受α（2）-抗纤溶酶的调节，表明这种酶参与宿主/病原体相互作用。分别以2.35埃和1.9埃的分辨率测定了天然形式和与异羟肟酸底物类似物复合的FBA-tb的晶体结构。而抑制剂附件上的纤溶酶原结合活性的FBA-TB没有影响，它与天然底物的酶，果糖1，6-二磷酸竞争，并证实了一个以前未知的反应机制与金属依赖性醛缩酶涉及招聘的催化锌离子的底物活性位点结合后。总之，我们的研究结果突出了FBA-tb作为针对复制和非复制杆菌的新型治疗靶点的潜力。
The search for antituberculosis drugs active against persistent bacilli has led to our interest in metallodependent class II fructose-1,6-bisphosphate aldolase (FBA-tb), a key enzyme of gluconeogenesis absent from mammalian cells. Knock-out experiments at the fba-tb locus indicated that this gene is required for the growth of Mycobacterium tuberculosis on gluconeogenetic substrates and in glucose-containing medium. Surface labeling and enzymatic activity measurements revealed that this enzyme was exported to the cell surface of M. tuberculosis and produced under various axenic growth conditions including oxygen depletion and hence by non-replicating bacilli. Importantly, FBA-tb was also produced in vivo in the lungs of infected guinea pigs and mice. FBA-tb bound human plasmin(ogen) and protected FBA-tb-bound plasmin from regulation by alpha(2)-antiplasmin, suggestive of an involvement of this enzyme in host/pathogen interactions. The crystal structures of FBA-tb in the native form and in complex with a hydroxamate substrate analog were determined to 2.35- and 1.9-angstrom resolution, respectively. Whereas inhibitor attachment had no effect on the plasminogen binding activity of FBA-tb, it competed with the natural substrate of the enzyme, fructose 1,6-bisphosphate, and substantiated a previously unknown reaction mechanism associated with metallodependent aldolases involving recruitment of the catalytic zinc ion by the substrate upon active site binding. Altogether, our results highlight the potential of FBA-tb as a novel therapeutic target against both replicating and non-replicating bacilli.