Biosynthetic mechanism for sunscreens of the biocontrol agent Lysobacter enzymogenes.
Biosynthetic mechanism for sunscreens of the biocontrol agent Lysobacter enzymogenes.
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生防剂溶酶杆菌防晒剂的生物合成机制
DOI：
10.1371/journal.pone.0066633
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发表时间：
2013
期刊：
影响因子：
3.7
通讯作者：
Du L
中科院分区：
文献类型：
--
作者：
Wang Y;Qian G;Li Y;Wang Y;Wang Y;Wright S;Li Y;Shen Y;Liu F;Du L
溶杆菌是一种广泛存在的环境细菌，是一种新型的生物防治剂和抗感染药物的新来源。到目前为止，很少有人投入到这些革兰氏阴性滑行细菌的生物学研究中。许多溶杆菌属物种的特征在于它们的黄橙色外观。利用转座子诱变技术，我们鉴定了一个独立的聚酮合成酶（PKS）基因簇，该基因簇是L.酶基因OH 11。在通过靶特异性缺失酮合酶（KS）、酰基载体蛋白或酮还原酶产生的“白色”突变体中，黄色色素被消除。光谱数据表明，该色素属于黄单胞菌素样芳基多烯。已知多烯型聚酮化合物通过模块化PKS（I型）而不是通过总是含有异二聚体KS-CLF（链长因子）作为关键催化组分的独立PKS（II型）生物合成。值得注意的是，该芳基多烯PKS复合物仅含有KS（ORF 17），而不含有CLF。相反，一个假设的蛋白质（ORF 16）位于紧邻ORF 17。ORF 16 -17同源物广泛存在于许多未表征的微生物基因组中，其中ORF 17同源物总是伴随着ORF 16同源物。ORF 16的缺失消除了色素的产生，同源性建模表明ORF 16与CLF的N-末端一半具有结构相似性。谷氨酰胺（Q166 A）是已知CLF的保守活性位点的点突变废除了色素的产生。“白色”突变体比野生型对UV/可见光辐射或H2 O2处理显著更敏感。这些结果揭示了II型PKS合成的多烯色素的第一个例子，并表明代谢产物作为溶杆菌“防晒霜”，对这些无处不在的环境生物的生存很重要。
Lysobacter are ubiquitous environmental bacteria emerging as novel biocontrol agents and new sources of anti-infectives. So far, very little effort has been invested in the study of the biology of these Gram-negative gliding bacteria. Many Lysobacter species are characterized by their yellow-orange appearance. Using transposon mutagenesis, we identified a stand-alone polyketide synthase (PKS) gene cluster required for the pigment production in L. enzymogenes OH11. The yellow pigments were abolished in the “white” mutants generated by target-specific deletions of ketosynthase (KS), acyl carrier protein, or ketoreductase. Spectroscopic data suggested that the pigments belong to xanthomonadin-like aryl polyenes. Polyene-type polyketides are known to be biosynthesized by modular PKS (Type I), not by stand-alone PKS (Type II) which always contain the heterodimer KS-CLF (chain-length factor) as the key catalytic component. Remarkably, this aryl polyene PKS complex only contains the KS (ORF17), but not the CLF. Instead, a hypothetical protein (ORF16) is located immediately next to ORF17. ORF16–17 homologs are widespread in numerous uncharacterized microbial genomes, in which an ORF17 homolog is always accompanied by an ORF16 homolog. The deletion of ORF16 eliminated pigment production, and homology modeling suggested that ORF16 shares a structural similarity to the N-terminal half of CLF. A point-mutation of glutamine (Q166A) that is the conserved active site of known CLF abolished pigment production. The “white” mutants are significantly more sensitive to UV/visible light radiation or H2O2 treatment than the wild type. These results unveil the first example of Type II PKS-synthesized polyene pigments and show that the metabolites serve as Lysobacter “sunscreens” that are important for the survival of these ubiquitous environmental organisms.
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影响因子：
16.8
作者：
Keatinge-Clay, A;Maltby, DA;Stroud, RM
通讯作者：
Stroud, RM
影响因子：
3.2
作者：
Goel, AK;Rajagopal, L;Sonti, RV
通讯作者：
Sonti, RV
影响因子：
4.8
作者：
Heath, RJ;Rock, CO
通讯作者：
Rock, CO
DOI：
10.1099/00207713-28-3-367
发表时间：
1978-01-01
期刊：
INTERNATIONAL JOURNAL OF SYSTEMATIC BACTERIOLOGY
影响因子：
--
作者：
CHRISTENSEN, P;COOK, FD
通讯作者：
COOK, FD
影响因子：
4.4
作者：
Kobayashi, DY;Reedy, RM;Yuen, GY
通讯作者：
Yuen, GY