The Perliminary Research For Gene Of Methylthioadenosine Phosphorylase (mtaA) Form Methylobacterium Sp. MB200

Methanol widely exists in industrial waste water. And it is not onlypollutes the environment but also harms to human health. Methylotrophicbacteria is a kind of microorganism which can take methanol as its onlycarbon source. In the experiment the bacteria has been screened inenvironment which can regard methanol as carbon source and product L-serine. Its can not only be useful to reduce the pollution of theenvironment but effective.Taking advantage of the pTnMod-RKm’ suicide plasmid and adifferent concentration of L-serine added in the medium,177mutationalstrains which were resistant to L-serine. Totally18genes had been clonedin mutants using the molecular biology tools.Through bioinformatics analysis, the mtaA cloned has94%andsimilarity with mtaA in Methylobacterium extorquens PA1in nucleotideand97%similarity with mtaA in Methylobacterium populi BJ001inamino acid. The mtaA cloned has876bp bases and codes for MTAPwhich belongs to nucleoside phosphorylase superfamily according to thefunctional domain analysis.It was be discovered that Methylobacteirum sp. MB200has MTAPenzyme activity which varied disciplinary as the different concentrationof L-serine. MB200was be structured with the pRK2013helper plasmidand expression vector pCM80underway a triparental mating.In order tostudy mtaA in M. sp. MB200and the its coding characteristic, MB200TBwere deficient in mtaA and MB200HB had recombinant plasmid withmtaA. After the test of enzymatic activity,it shown that mtaA has L-serinefeedback inhibition. In the experiment, different concentration of L-serine was added inMMI medium. M. sp. MB200, MB200TB and MB200HB had beenstudied in tolerance with L-serine. It shown that MB200TB was moretolerant with high concentration of L-serine than MB200and MB200HB.mtaA deficiency was favorable in enhance the L-serine tolerance.According to the study of growth situation of M. sp. MB200,MB200TBand MB200HB, it was almost the same in MB200TB, MB200andMB200HB. The mutant in mtaA had no influence in the growth ofbacteria.In the end by the preparation of resting cells system, the L-serineproduction situation of M. sp. MB200,MB200TB and MB200HB hadbeen analysized. It is resulted that recombinant MB200TB andMB200HB had more production than parent strain.