Bacillus megaterium CYP102A1 oxidation of acyl homoserine lactones and acyl homoserines
Bacillus megaterium CYP102A1 oxidation of acyl homoserine lactones and acyl homoserines
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DOI：
10.1021/bi701945j
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发表时间：
2007-12-18
期刊：
影响因子：
2.9
通讯作者：
Haines, Donovan C.
中科院分区：
文献类型：
--
作者：
Chowdhary, Puneet K.;Keshavan, Neela;Haines, Donovan C.
群体感应是细菌通过合成和检测小分子信号来感知自身群体密度的能力，近年来受到了极大的关注。酰基高丝氨酸内酯（AHL）是一类重要的群体感应信号分子。在自然界中，一些本身不合成AHLs的细菌已经发展出通过裂解酰胺键或内酯环来降解这些化合物的能力。通过灭活竞争细菌使用的这种信号，降解微生物被认为获得了竞争优势。在这项工作中，我们报告说，CYP 102 A1，一个广泛研究的细胞色素P450从巨大芽孢杆菌，是能够非常有效的氧化AHL和他们的内酯水解产物酰基高丝氨酸。这种酶的先前已知底物脂肪酸也可以通过水解AHL的酰胺在自然界中形成，因此CYP 102 A1能够灭活活性母体化合物和在自然界中观察到的两种已知阿勒灭活途径的产物。阿勒氧化主要发生在酰基链的omega-1、omega-2和omega-3碳上，类似于这种酶对脂肪酸的众所周知的活性。酰基高丝氨酸及其内酯是比脂肪酸更好的CYP 102 A1底物。对氧化产物的群体感应活性的生物测定表明，亚末端羟基化的AHL具有群体感应活性，但活性比母体化合物低18倍。在体内，B.巨大芽孢杆菌通过依赖于CYP 102 A1的机制使AHLs失活，该机制必须涉及进一步螯合或代谢产物的额外组分，从而消除其群体感应活性。细胞色素P450氧化AHLs代表一个重要的新的机制，群体淬灭。
Quorum sensing, the ability of bacteria to sense their own population density through the synthesis and detection of small molecule signals, has received a great deal of attention in recent years. Acyl homoserine lactones (AHLs) are a major class of quorum sensing signaling molecules. In nature, some bacteria that do not synthesize AHLs themselves have developed the ability to degrade these compounds by cleaving the amide bond or the lactone ring. By inactivating this signal used by competing bacteria, the degrading microbe is believed to gain a competitive advantage. In this work we report that CYP102A1, a widely studied cytochrome P450 from Bacillus megaterium, is capable of very efficient oxidation of AHLs and their lactonolysis products acyl homoserines. The previously known substrates for this enzyme, fatty acids, can also be formed in nature by hydrolysis of the amide of AHLs, so CYP102A1 is capable of inactivating the active parent compound and the products of both known pathways for AHL inactivation observed in nature. AHL oxidation primarily takes place at the omega-1, omega-2, and omega-3 carbons of the acyl chain, similar to this enzyme's well-known activity on fatty acids. Acyl homoserines and their lactones are better substrates for CYP102A1 than fatty acids. Bioassay of the quorum sensing activity of oxidation products reveals that the subterminally hydroxylated AHLs exhibit quorum sensing activity, but are 18-fold less active than the parent compound. In vivo, B. megaterium inactivates AHLs by a CYP102A1 dependent mechanism that must involve additional components that further sequester or metabolize the products, eliminating their quorum sensing activity. Cytochrome P450 oxidation of AHLs represents an important new mechanism of quorum quenching.