Quinolone resistance-associated amino acid substitutions affect enzymatic activity of Mycobacterium leprae DNA gyrase
Quinolone resistance-associated amino acid substitutions affect enzymatic activity of Mycobacterium leprae DNA gyrase
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DOI：
10.1080/09168451.2017.1314757
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发表时间：
2017-04
期刊：
影响因子：
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通讯作者：
Tomoyuki Yamaguchi;Kazumasa Yokoyama;C. Nakajima;Yasuhiko Suzuki
中科院分区：
文献类型：
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作者：
Tomoyuki Yamaguchi;Kazumasa Yokoyama;C. Nakajima;Yasuhiko Suzuki
喹诺酮类药物是治疗麻风病的重要抗菌药物。虽然众所周知，DNA促旋酶的突变是喹诺酮类药物耐药的原因，但这些突变对酶活性的影响还有待深入研究。因此，我们进行了体外试验，以观察野生型和突变的M。麻风DNA回旋酶氨基酸替换为Ala91Val的DNA促旋酶活性最高。具有Gly89Cys的DNA促旋酶显示出最低水平的活性，尽管在临床菌株中被发现，但是如果以足够的浓度施用，则其像野生型一样超螺旋DNA。此外，模式的时间依赖性转换从松弛的环状DNA超螺旋DNA的DNA回旋酶与临床上未报道的Asp95Gly和Asp95Asn被观察到的是不同于那些由其他的DNA回旋酶。DNA旋转酶超螺旋活性在很大程度上改变了喹诺酮类药物的耐药性。
Quinolones are important antimicrobials for treatment of leprosy, a chronic infectious disease caused by Mycobacterium leprae. Although it is well known that mutations in DNA gyrase are responsible for quinolone resistance, the effect of those mutations on the enzymatic activity is yet to be studied in depth. Hence, we conducted in vitro assays to observe supercoiling reactions of wild type and mutated M. leprae DNA gyrases. DNA gyrase with amino acid substitution Ala91Val possessed the highest activity among the mutants. DNA gyrase with Gly89Cys showed the lowest level of activity despite being found in clinical strains, but it supercoiled DNA like the wild type does if applied at a sufficient concentration. In addition, patterns of time-dependent conversion from relaxed circular DNA into supercoiled DNA by DNA gyrases with clinically unreported Asp95Gly and Asp95Asn were observed to be distinct from those by the other DNA gyrases. DNA gyrase supercoiling activity largely changed by acquisition of quinolone resistance.