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Hokkaido University Collection of Scholarly and Academic Papers >
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Isocitrate dehydrogenase isozymes from a psychrotrophic bacterium, Pseudomonas psychrophila
| Title: | Isocitrate dehydrogenase isozymes from a psychrotrophic bacterium, Pseudomonas psychrophila |
| Authors: | Matsuo, Shougo Browse this author | | Shirai, Haruna Browse this author | | Takada, Yasuhiro Browse this author |
| Keywords: | Isocitrate dehydrogenase | | Isozymes | | Psychrotrophic bacterium | | Pseudomonas psychrophila | | Site-directed mutagenesis |
| Issue Date: | Aug-2010 |
| Publisher: | Springer Berlin / Heidelberg |
| Journal Title: | Archives of Microbiology |
| Volume: | 192 |
| Issue: | 8 |
| Start Page: | 639 |
| End Page: | 650 |
| Publisher DOI: | 10.1007/s00203-010-0595-3 |
| PMID: | 20549192 |
| Abstract: | The genes encoding monomer- and dimer-type isocitrate dehydrogenase (IDH) isozymes from a psychrotrophic bacterium, Pseudomonas psychrophila, were cloned and sequenced. Open reading frames of the genes were 2,226 and 1,257 bp in length and corresponded to polypeptides composed of 741 and 418 amino acids, respectively. The deduced amino acid sequences showed high sequence identity with those of psychrophilic bacteria, Colwellia maris and Colwellia psychrerythraea, (about 70% identity) and the respective types of the putative IDH genes from other bacteria of genus Pseudomonas (more than 80% identity). The two genes were located in opposite direction from each other with a spacer of 463 bases in the order of dimeric and monomeric IDH genes on the chromosomal DNA, but analyses of northern blotting and 5'-terminal regions of the mRNAs revealed that they are transcribed independently. The expression of monomer- and dimer-type IDH genes in C. maris are known to be cold- and acetate-inducible, respectively, while only slight inductions by low temperature and/or acetate were observed in the expression of the P. psychrophila monomer- and dimer-type IDH genes. Both of these IDH isozymes overproduced in Escherichia coli showed mesophilic properties, in contrast with monomer- and dimer-type IDHs of C. maris as cold-adapted and mesophilic enzymes, respectively. The substitution of Glu55 residue in the P. psychrophila monomeric IDH for Lys, which is the corresponding residue conserved between the cold-adapted monomeric IDHs from C. maris and C. psychrerythraea, by site-directed mutagenesis resulted in the decreased thermostability and the lowered optimum temperature of activity, suggesting that this residue is involved in the mesophilic properties of the P. psychrophila monomeric IDH. |
| Rights: | The original publication is available at www.springerlink.com |
| Type: | article (author version) |
| URI: | http://hdl.handle.net/2115/46864 |
| Appears in Collections: | 生命科学院・先端生命科学研究院 (Graduate School of Life Science / Faculty of Advanced Life Science) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)
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Submitter: 高田 泰弘
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