title: Metagenome resource for D-serine utilization in a DsdA-disrupted Escherichia coli.
abstract: To find alternative genetic resources for D-serine dehydratase (E.C. 4.3.1.18, dsdA) mediating the deamination of D-serine into pyruvate, metagenomic libraries were screened. The chromosomal dsdA gene of a wild-type Escherichia coli W3110 strain was disrupted by inserting the tetracycline resistance gene (tet), using double-crossover, for use as a screening host. The W3110 dsdA::tet strain was not able to grow in a medium containing D-serine as a sole carbon source, whereas wild-type W3110 and the complement W3110 dsdA::tet strain containing a dsdA-expression plasmid were able to grow. After introducing metagenome libraries into the screening host, a strain containing a 40-kb DNA fragment obtained from the metagenomic souce derived from a compost was selected based on its capability to grow on the agar plate containing D-serine as a sole carbon source. For identification of the genetic resource responsible for the D-serine degrading capability, transposon- micron was randomly inserted into the 40-kb metagenome. Two strains that had lost their D-serine degrading ability were negatively selected, and the two 6-kb contigs responsible for the D-serine degrading capability were sequenced and deposited (GenBank code: HQ829474.1 and HQ829475.1). Therefore, new alternative genetic resources for D-serine dehydratase was found from the metagenomic resource, and the corresponding ORFs are discussed.
authors.affiliation: Departments of Biotechnology, Catholic University of Korea, Bucheon, Gyeonggi 420-743, Korea.
authors.forename: Mi Young
authors.initials: MY
authors.lastname: Lim
authors.forename: Hyo Jeong
authors.initials: HJ
authors.lastname: Lee
authors.forename: Pil
authors.initials: P
authors.lastname: Kim
mesh_terms: D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000235:genetics* / Q000378:metabolism; D012695:L-Serine Dehydratase / Q000235:genetics* / Q000378:metabolism; D054892:Metagenome; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D012694:Serine / Q000378:metabolism*
chemical_list: D029968:Escherichia coli Proteins; D012694:Serine; D012695:L-Serine Dehydratase