Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK.
Protein J. 2009 Aug;28(6):281-93. doi: 10.1007/s10930-009-9193-0.
Arylamine N-acetyltansferase (NAT) from Mycobacterium tuberculosis (TBNAT) is a potential drug target for anti-tubercular therapy. Recombinant TBNAT is much less soluble and is produced in lower yields than the closely related NAT from Mycobacterium marinum (MMNAT). In order to explore MMNAT as a model for TBNAT in drug discovery, we compare the two mycobacterial NAT enzymes. Two site-directed mutants of MMNAT have been prepared and characterised: MMNAT71, Tyr --> Phe and MMNAT209, Met --> Thr, in which residues within 6 A of the active-site cysteine have been replaced with the corresponding residue from TBNAT. Two chimeric proteins have also been produced in which the third domain of MMNAT has been replaced by the third domain of TBNAT and vice versa. The activity profile of the chimeric proteins suggests a role for the third domain in the evolutionary divergence of NAT between these closely related mycobacterial species.
结核分枝杆菌中的芳基胺 N-乙酰转移酶（NAT）是抗结核治疗的潜在药物靶点。与密切相关的海分枝杆菌 NAT（MMNAT）相比，重组 TBNAT 的可溶性更低，产量也更低。为了探索 MMNAT 作为药物发现中 TBNAT 的模型，我们比较了两种分枝杆菌 NAT 酶。已经制备并表征了 MMNAT 的两个定点突变体：MMNAT71，Tyr --> Phe 和 MMNAT209，Met --> Thr，其中活性位点半胱氨酸 6A 内的残基被来自 TBNAT 的相应残基取代。还产生了两种嵌合蛋白，其中 MMNAT 的第三个结构域被 TBNAT 的第三个结构域取代，反之亦然。嵌合蛋白的活性谱表明，第三个结构域在这些密切相关的分枝杆菌物种之间的 NAT 进化分歧中起作用。
