Training in structural biology & glycobiology

项目摘要 细菌的黏附和定植对细菌的适合性和致病力至关重要。尽管在理解这一关键的生物学过程方面已经取得了很大的进展，但分子细节在很大程度上是未知的。我们在模式生物副血链球菌中对链球菌菌毛相关蛋白(Fap1)的先驱研究揭示了一个新的细菌粘附素家族，富含丝氨酸的重复糖蛋白(SRRPs)。这一家族蛋白由编码糖基转移蛋白和辅助分泌蛋白的基因簇合成，在致病性链球菌和葡萄球菌中高度保守，在细菌与宿主细胞的相互作用和致病机制中发挥重要作用。遗传和生化研究表明，Fap1的糖基化是由两个假定的糖基转移酶Gtf1和Gtf2组成的两酶异二聚体复合体启动的。GTF复合体催化GlcNAc转移到Fap1的富含丝氨酸的位置。吴博士将利用他的休假时间接受结构生物学和糖生物学方面的培训，以进一步探索SRRPs生物发生的分子细节。拟议的培训将在伦敦帝国理工学院史蒂夫·马修斯博士和安妮·戴尔·S博士的实验室进行。马修斯博士和戴尔博士都是各自领域的顶尖专家，对吴博士和S博士的研究领域非常感兴趣，过去曾与吴博士合作过不同的研究项目。在他们的实验室接受培训将使PI更好地了解结构生物学和糖生物学，并帮助PI将这种最先进的研究方法应用于他目前的研究，并开发新的研究计划，探索SRRP对致病链球菌和葡萄球菌的功能贡献。S的长期目标是确定SRRPs的生物发生如何促进细菌的毒力，以及我们如何利用新的途径来设计疗法。具体目标1：通过解决参与SRRPs糖基化的糖基转移酶的三维高分辨结构来获得结构生物学方面的培训。吴博士将在这一具体目标上花费3-4个月的时间。具体目标2：通过表征附着在SRRP上的糖链结构，获得糖生物学方面的培训。吴博士将在这一具体目标上花费3-4个月的时间。由于SRRPs在致病链球菌和葡萄球菌中高度保守，破译调控其生物发生的分子事件不仅有助于我们了解口腔菌斑形成的生物学，而且为设计SRRPs介导的细菌感染的新治疗靶点提供了新的信息，这是PI的一个新的研究方向。

Project Summary Bacterial adhesion and colonization are crucial for bacterial fitness and virulence. Despite the great progress has been made in understanding of this critical biological process, molecular details are largely unknown. Our pioneer studies of a streptococcal fimbriae-associated protein (Fap1) in a model organism, Streptococcus parasanguinis have revealed a new family of bacterial adhesins, serine-rich repeat glycoproteins (SRRPs). This family of proteins is synthesized by a gene cluster coding for glycosyltransferaes and accessory secretion proteins; they are highly conserved in pathogenic streptococci and staphylococci, and play important roles in bacterial interaction with the host cells and pathogenesis. Genetic and biochemical studies have led us to conclude that glycosylation of Fap1 is initiated by a two enzyme heterodimeric complex that is composed by two putative glycosyltransferases Gtf1 and Gtf2. The Gtf complex catalyzes the transfer of GlcNAc to the serine-rich sites of Fap1. Dr. Wu will use his sabbatical leave to obtain training in structural biology and glycobiology to further explore molecular details regarding biogenesis of SRRPs. The proposed training will take place in Imperial College London in Dr. Steve Matthews and Dr. Anne Dell¿s laboratories. Drs. Matthews and Dell are the leading experts in their field, and very interested in Dr. Wu¿s research area and have already collaborated with Dr. Wu in the past on different research projects. Training in their laboratories would allow the PI have better understanding of structural biology and glycobiology, and help the PI apply this state of art research approaches in his current research and develop new research programs which explore functional contribution of SRRPs to pathogenic streptococci and staphylococci. The PI¿s long-term goals are to determine how biogenesis of SRRPs contributes to bacterial virulence and how we can harness the new pathway to design therapeutics. Specific Aim 1: Obtain training in structural biology by solving 3-D high resolution structure of glycosyltransferases that are involved in glycosylation of SRRPs. Dr. Wu will spend 3-4 months on this specific aim. Specific Aim 2: Obtain training in glycobiology by charactering glycan structures attached to SRRPs. Dr. Wu will spend 3-4 months on this specific aim. As SRRPs are highly conserved in pathogenic streptococci and staphylococci, deciphering the molecular events that modulates their biogenesis will not only help us to understand biology of the plaque formation in the oral cavity but also provide new information useful for the design of novel therapeutic targets towards bacterial infections mediated by SRRPs, a new research direction for the PI.