ACTIVATION OF LYSINE 2,3-AMINOMUTASE

赖氨酸2，3-氨基变位酶催化L-赖氨酸和L-赖氨酸的相互转化， β-赖氨酸这个反应是第一个承诺的步骤， 允许梭菌使用赖氨酸作为碳、氮的来源， 能源梭菌也使用β-L-赖氨酸来生物合成许多 抗生素。许多研究表明， 反应途径含有碳中心自由基。这样做的目的 研究的目的是确定酶如何与其辅因子结合 （磷酸吡哆醛，铁硫簇[Fe-S]和S- 腺苷甲硫氨酸（SAM））产生这些自由基。工作假设 是当电子从[Fe-S]转移到SAM时，SAM均裂为 产生甲硫氨酸和5 ′-脱氧腺苷自由基（5 ′-dA.）这是 负责启动催化作用。为了测试这个模型， 将使用电子顺磁共振和穆斯堡尔谱 以评估催化过程中[Fe-S]氧化态的变化。 此外，将使用以下方法验证该变化的动力学能力： 快速动力学方法最后，将合成SAM的类似物， 作为[Fe-S]和SAM之间通信的探针， 切割事件，以及用于评估5'-dA产生的陷阱。这 所提出的自由基生成系统也存在于核糖核苷酸中 厌氧生长的E.大肠杆菌，以及丙酮酸甲酸 裂解酶，在这一领域的研究可能会提供线索的新方法， 抑制厌氧细菌。

Lysine 2,3-aminomutase catalyzes the interconversion of L-lysine and L- beta-lysine. This reaction is the first committed step in the pathway that allows Clostridia to use Lysine as a source of carbon, nitrogen, and energy. Clostridia also use beta-L-lysine for the biosynthesis of a number of antibiotics. Numerous studies indicate that several intermediates on the reaction pathway contain carbon-centered radicals. The purpose of this study is to determine how the enzyme in combination with its cofactors (pyridoxal phosphate, an iron-sulfur cluster [Fe-S], and S- adenosylmethionine (SAM)) generates these radicals. The working hypothesis is that upon electron transfer to SAM from [Fe-S], SAM homolyzes to generate methionine and a 5'-deoxyadenosyl radical (5'-dA.) which is responsible for initiating catalysis. In order to test this model, electron paramagnetic resonance and Mossbauer spectroscopies will be used to assess a change in the oxidation state of the [Fe-S] during catalysis. In addition, the kinetic competence of this change will be verified using rapid kinetics methods. Lastly, analogs of SAM will be synthesized and used as probes for communication between the [Fe-S] and SAM during the cleavage event, as well as traps to assess the production of 5'-dA.. This proposed radical generating system is also present in the ribonucleotide reductase from anaerobically growing E. coli, as well as pyruvate formate lyase, and research in this area may offer clues for new methods of inhibiting anaerobic bacteria.