CRYSTAL STRUCTURES OF THE GLYCOPEPTIDE SULFOTRANSFERASE TEG12

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 万古霉素和替考拉宁是临床上用于治疗许多革兰氏阳性细菌感染的糖肽类抗生素，包括耐甲氧西林金黄色葡萄球菌(MRSA)。在它们的生物合成过程中，这个抗生素家族的每个成员都被一组独特的终末酶所功能化，其中包括糖基、酰基、甲基和磺基转移酶。近年来，发现新的糖肽同系物的速度有所放缓，因为识别新的生物多样性变得越来越困难，根据这些生物多样性可以表征新的分子。自然界中存在的绝大多数细菌仍然不愿培养，因此它们代表了一种潜在的小分子的新来源。虽然这些细菌产生的代谢物不能用标准的微生物方法来表征，但可以直接从环境样本中提取DNA，并分析这些DNA中编码新天然产物生物合成的序列。在对从沙漠土壤中提取的DNA的调查中，我们发现了一个生物合成基因簇(TEG基因簇)，它被预测为编码第一个多硫化糖肽同系物的生物合成。TEG基因簇包含三个密切相关的磺基转移酶(Teg12、Teg13和Teg14)，它们在三个独特的位置上具有类似替考拉宁的糖肽，它们结合在一起可以产生7种不同的硫酸盐化模式。已从培养的细菌中鉴定出150多种不同的糖基化、卤化和烷基化糖肽同源物，但通过对这些相同微生物的研究，只鉴定出三种硫酸盐同源物。酶促合成阴离子糖肽为获得更多的阴离子同系物提供了一种简便的方法。TEG磺基转移酶的高分辨率X射线晶体结构应该提供有关这些酶如何被设计来产生额外的阴离子糖肽的洞察力，这些糖肽可以针对临床相关的耐药细菌进行评估。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Vancomycin and teicoplanin are glycopeptide antibiotics used clinically to treat many gram-positive bacterial infections, including methicillin resistant Staphylococcus aureus (MRSA). During their biosynthesis, each member of this family of antibiotics is functionalized by a unique set of finishing enzymes that includes glycosyl, acyl, methyl and sulfo- transferases. The discovery of new glycopeptide congeners has slowed in recent years as it has become increasingly difficult to identify new biodiversity from which novel molecules might be characterized. The vast majority of bacteria present in nature remain recalcitrant to culturing and therefore they represent a potentially novel source of small molecules. Although metabolites produced by these bacteria cannot be characterized using standard microbiological methods, it is possible to extract DNA directly from environmental samples and analyze this DNA for sequences that encode the biosynthesis of novel natural products. In a survey of DNA extracted from desert soil, we uncovered a biosynthetic gene cluster (the TEG gene cluster) that is predicted to encode the biosynthesis of the first polysulfated glycopeptide congeners. The TEG gene cluster contains three closely related sulfotransferases (Teg12, 13, and 14) that sulfate teicoplanin like glycopeptides at three unique sites, and in combination, they can be used to produce 7 different sulfation patterns. Over 150 different glycosylated, halogenated, and alkylated glycopeptide congeners have been characterized from cultured bacteria, yet only three sulfated congeners have been identified from studying these same microbes. The enzymatic synthesis of anionic glycopeptides could provide a facile means to access additional anionic congeners. High-resolution X-ray crystal structures of the TEG sulfotransferases should provide insight into how these enzymes might be engineered to generate additional anionic glycopeptides that could be evaluated against clinically relevant drug resistant bacteria.