Decaprenylphosphoryl-β-D-Ribose 2′-Epimerase, the Target of Benzothiazinones and Dinitrobenzamides, Is an Essential Enzyme in Mycobacterium smegmatis
Decaprenylphosphoryl-β-D-Ribose 2′-Epimerase, the Target of Benzothiazinones and Dinitrobenzamides, Is an Essential Enzyme in Mycobacterium smegmatis
复制标题
DOI：
10.1371/journal.pone.0016869
复制
发表时间：
2011-02-08
期刊：
影响因子：
3.7
通讯作者：
Coppel, Ross L.
中科院分区：
文献类型：
--
作者：
Crellin, Paul K.;Brammananth, Rajini;Coppel, Ross L.
背景：棒状杆菌亚目细菌独特的细胞壁对包括结核分枝杆菌和麻风分枝杆菌在内的重要人类病原体的生长和存活至关重要。分枝杆菌耐药是一个日益普遍的发展，使鉴定新的抗菌素成为一个优先事项。最近的研究表明，有效的抗分枝杆菌化合物苯并噻唑酮和二硝基苯并胺类化合物对DprE1有活性，DprE1是十戊烯基磷酸核糖29外基酶的一个亚基，形成十戊烯基磷酸阿拉伯糖，后者是分枝杆菌细胞壁生物合成的阿拉伯糖供体。尽管利用耻垢分枝杆菌鉴定了DprE1作为这些新型抗菌剂的靶点，并将其用于探索耐药机制，但DprE1在该物种中的重要性从未被研究过。事实上，在任何种类的分枝杆菌中都没有获得DprE1的必要性的直接实验证据。方法/主要发现：本研究构建了一株针对耻垢分枝杆菌dprE1同源基因MSMEG_6382的条件基因敲除菌株。只有在MSMEG_6382的质粒编码拷贝存在的情况下，MSMEG_6382的染色体拷贝才可能被破坏。这种“拯救”质粒从细菌种群中固化导致生长停止，证明了基因的重要性。结论/意义：本研究为分枝杆菌中DprE1的必要性提供了第一个直接的实验证据。DprE1在耻毛分枝杆菌中的重要性，以及它在所有已测序的分枝杆菌基因组中的保守性，表明十戊烯基磷酸基阿拉伯糖合成在所有分枝杆菌中都是必不可少的。我们的研究结果表明，尽管该物种具有相对较大的编码能力，但在臭毛单胞菌中，十烯丙烯磷基阿拉伯糖的合成缺乏冗余性，并表明没有其他阿拉伯糖供体存在于细胞壁的生物合成中。总之，本研究进一步验证了DprE1作为新型抗分枝杆菌药物的一个有希望的靶点。
Background: The unique cell wall of bacteria of the suborder Corynebacterineae is essential for the growth and survival of significant human pathogens including Mycobacterium tuberculosis and Mycobacterium leprae. Drug resistance in mycobacteria is an increasingly common development, making identification of new antimicrobials a priority. Recent studies have revealed potent anti-mycobacterial compounds, the benzothiazinones and dinitrobenzamides, active against DprE1, a subunit of decaprenylphosphoribose 29 epimerase which forms decaprenylphosphoryl arabinose, the arabinose donor for mycobacterial cell wall biosynthesis. Despite the exploitation of Mycobacterium smegmatis in the identification of DprE1 as the target of these new antimicrobials and its use in the exploration of mechanisms of resistance, the essentiality of DprE1 in this species has never been examined. Indeed, direct experimental evidence of the essentiality of DprE1 has not been obtained in any species of mycobacterium.Methodology/Principal Findings: In this study we constructed a conditional gene knockout strain targeting the ortholog of dprE1 in M. smegmatis, MSMEG_6382. Disruption of the chromosomal copy of MSMEG_6382 was only possible in the presence of a plasmid-encoded copy of MSMEG_6382. Curing of this "rescue'' plasmid from the bacterial population resulted in a cessation of growth, demonstrating gene essentiality.Conclusions/Significance: This study provides the first direct experimental evidence for the essentiality of DprE1 in mycobacteria. The essentiality of DprE1 in M. smegmatis, combined with its conservation in all sequenced mycobacterial genomes, suggests that decaprenylphosphoryl arabinose synthesis is essential in all mycobacteria. Our findings indicate a lack of redundancy in decaprenylphosphoryl arabinose synthesis in M. smegmatis, despite the relatively large coding capacity of this species, and suggest that no alternative arabinose donors for cell wall biosynthesis exist. Overall, this study further validates DprE1 as a promising target for new anti-mycobacterial drugs.