UNVEILING NOVEL ASPECTS OF D-AMINO ACID METABOLISM IN THE MODEL BACTERIUM PSEUDOMONAS PUTIDA KT2440

摘要: OF DISSERTATION UNVEILING NOVEL ASPECTS D-AMINO ACID METABOLISM IN THE MODEL BACTERIUM PSEUDOMONAS PUTIDA KT2440 D-amino acids (D-AAs) are the α-carbon enantiomers of L-amino (LAAs), building blocks proteins in known organisms. It was largely believed that D-AAs unnatural and must be toxic to most organisms, as they would compete with L-counterparts for protein synthesis. Recently, new methods have been developed allow scientists chromatographically separate two AA stereoisomers. Since time, it has discovered vital molecules detected many The work this dissertation focuses on their place bacterial metabolism. This specific area selected due abundance bacteria-rich environments knowledge part several processes, such peptidoglycan synthesis, biofilm disassembly, sporulation. We focused bacterium Pseudomonas putida which inhabits densely populated plant rhizosphere. Due its versatility cosmopolitan character, provided an excellent system study D-AA In first chapter, we a approach identify genes encoding enzymes acting D-AAs, collectively amino acid racemases. Using novel method, identified three racemases encoded by genome P. KT2440. All were subsequently cloned purified homogeneity, followed complete biochemical characterization. aim second chapter understand role peculiar broad-spectrum racemase Alr one. After constructing markerless deletion cognate gene, conducted variety phenotypic assays led model catabolic pathway involves D-ornithine intermediate. identifies time numerous rhizosphere-dwelling bacteria capable catabolizing D-AAs. Overall, contributes understanding catabolism aims stimulate future efforts research area.