title: Intracellular expression of Vitreoscilla hemoglobin improves S-adenosylmethionine production in a recombinant Pichia pastoris.
abstract: To develop an efficient way to produce S-adenosylmethionine (SAM), methionine adenosyltransferase gene (mat) from Streptomyces spectabilis and Vitreoscilla hemoglobin gene (vgb) were coexpressed intracellularly in Pichia pastoris, both under control of methanol-inducible promoter. Expression of mat in P. pastoris resulted in about 27 times higher specific activity of methionine adenosyltransferase (SMAT) and about 19 times higher SAM production relative to their respective control, suggesting that overexpression of mat could be used as an efficient method for constructing SAM-accumulating strain. Under induction concentration of 0.8 and 2.4% methanol, coexpression of vgb improved, though to different extent, cell growth, SAM production, and respiratory rate. However, the effects of VHb on SAM content (specific yield of SAM production) and SMAT seemed to be methanol concentration-dependent. When cells were induced with 0.8% methanol, no significant effects of VHb expression on SAM content and specific SMAT could be detected. When the cells were induced with 2.4% methanol, vgb expression increased SAM content significantly and depressed SMAT remarkably. We suggested that under our experimental scheme, the presence of VHb might improve ATP synthesis rate and thus improve cell growth and SAM production in the recombinant P. pastoris.
authors.affiliation: State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 200237 Shanghai, People's Republic of China.
authors.forename: Huaxin
authors.initials: H
authors.lastname: Chen
authors.forename: Ju
authors.initials: J
authors.lastname: Chu
authors.forename: Siliang
authors.initials: S
authors.lastname: Zhang
authors.forename: Yingping
authors.initials: Y
authors.lastname: Zhuang
authors.forename: Jiangchao
authors.initials: J
authors.lastname: Qian
authors.forename: Yonghong
authors.initials: Y
authors.lastname: Wang
authors.forename: Xiaoqing
authors.initials: X
authors.lastname: Hu
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D015966:Gene Expression Regulation, Fungal / Q000187:drug effects; D005822:Genetic Vectors / Q000235:genetics; D006454:Hemoglobins / Q000235:genetics / Q000378:metabolism*; D000432:Methanol / Q000494:pharmacology; D008716:Methionine Adenosyltransferase / Q000235:genetics / Q000378:metabolism; D008957:Models, Genetic; D010843:Pichia / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D011401:Promoter Regions, Genetic / Q000235:genetics; D011994:Recombinant Proteins / Q000378:metabolism; D012436:S-Adenosylmethionine / Q000096:biosynthesis*; D014170:Transformation, Genetic; D054793:Truncated Hemoglobins
chemical_list: D001426:Bacterial Proteins; D006454:Hemoglobins; D011994:Recombinant Proteins; D054793:Truncated Hemoglobins; C082613:hemoglobin protein, Vitreoscilla; D012436:S-Adenosylmethionine; D008716:Methionine Adenosyltransferase; D000432:Methanol