FUNCTIONAL PROMISCUITY IN O-SUCCINYLBENZOATE SYNTHASE

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者所在的机构。 这个项目的目标是确定的结构基础上的催化杂合酶o-琥珀酰苯甲酸合酶（OSBS），烯醇化酶超家族的成员。OSBS家族的成员可以共享低至15%的同一性，并且该家族中唯一保守的残基也在烯醇化酶超家族的催化不同反应的其他成员中保守。这表明，虽然OSBS功能在进化过程中一直保持，但决定这种功能的残基和结构已经分化进化，并且不保守。我们正在确定OSBS催化的结构基础，通过使用结构比较来合理设计预测会影响OSBS活性的突变。 此外，OSBS家族的一个分支的许多成员催化第二反应，N-琥珀酰氨基酸外消旋化（NSAR）。我们正在进行结构、系统发育和诱变研究，以确定OSBS家族的一些成员如何催化NSAR反应，而其他成员则不能。该项目将利用几个RBVI资源，包括Chimera，结构功能链接数据库，以及通过RBVI可用的软件，如GCG和MrBayes。比较OSBS家族的结构、功能和进化将有助于我们理解蛋白质的功能可塑性以及结构如何介导功能。

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. The goal of this project is to determine the structural basis of catalytic promiscuity in the enzyme o-Succinylbenzoate synthase (OSBS), a member of the enolase superfamily. Members of the OSBS family can share as little as 15% identity, and the only conserved residues in the family are also conserved in other members of the enolase superfamily which catalyze different reactions. This suggests that although OSBS function has been maintained during the course of evolution, the residues and structures that determine this function have evolved divergently and are not conserved. We are determining the structural basis for OSBS catalysis by using structural comparisons to rationally design mutations that are predicted to affect OSBS activity. In addition, many members of one branch of the OSBS family catalyze a second reaction, N-succinylamino acid racemization (NSAR). We are performing structural, phylogenetic, and mutagenesis studies to determine how some members of the OSBS family can catalyze the NSAR reaction while others cannot. This project will utilize several RBVI resources, including Chimera, the Structure Function Linkage Database, and software available through RBVI such as GCG and MrBayes. Comparing structures, function and evolution of the OSBS family will add to our understanding about the functional plasticity of proteins and how structure mediates function.