| The decolorization activity of tamed Rhodopseudomonas palustris N strain under different outer circumstance conditions was studied. The results showed that temperature 25-30℃, pH7.0, anaerobic and illuminated conditions were optimum for decolorization.When reactive violet KBR was decolorized as sole source of carbon and energy of N strain, the decolorization rate of reactive violet KBR was significantly correlative to cell concentration, however the decolorization specific activity of N strains was not affected markedly by cell concentration. In addition, the growing of cells in the process of decolorization implicated the exponential growth phase of N strain lagged behind that of decolorization. Further experiment of decolorization by different carbon source demonstrated that N strain firstly degraded reactive violet KBR because of its detoxication, then entered the exponential growth.Previous test verified that Rhodopsedomonas palustris had a good ability of decolorization. Nucleic acid sequences of azoreduclase were searched and blasted in GenBank. A pair of primers based on the conserved regions were designed. A specific fragment was amplified by PCR from the plasmid of Rhodopsedomonas palustris and sequenced.The sequence contained a complete 471bp ORF (Open Reading Frame) . BLAST in GenBank indicated that it is novel gene named PAR-1.The characteristics of the protein coded by this gene were analyzed by bioinformatics. The result showed that this protein was instable, p1 9.65, located in bacterial inner membrane, and composed of Alpha helix, extrended strand and random coil. There was a srong transmembrance domain and contained some conserved sites such as protein dinase C phosphorylation. This gene was inserted into expressing vector pGEX-4T-1, which could express a GST fusion protein in E.coli.strain BL21(DE3) by IPTG inducing. The target fusion protein about 48KD was detected by SDS-PAGE. Slight azoreductase activity was obsearved in E.coli cell suspension. |
