Possible involvement of an FKBP family member protein from a psychrotrophic bacterium Shewanella sp. SIB1 in cold-adaptation.
A psychrotrophic bacterium Shewanella sp. strain SIB1 was grown at 4 and 20 degrees C, and total soluble proteins extracted from the cells were analyzed by two-dimensional polyacrylamide gel electrophoresis. Comparison of these patterns showed that the cellular content of a protein with a molecular mass of 28 kDa and an isoelectric point of four greatly increased at 4 degrees C compared to that at 20 degrees C. Determination of the N-terminal amino acid sequence, followed by the cloning and sequencing of the gene encoding this protein, revealed that this protein is a member of the FKBP family of proteins with an amino acid sequence identity of 56% to Escherichia coli FKBP22. This protein was overproduced in E. coli in a His-tagged form, purified, and analyzed for peptidyl-prolyl cis-trans isomerase activity. When this activity was determined by the protease coupling assay using N-succinyl-Ala-Leu-Pro-Phe-p-nitroanilide as a substrate at various temperatures, the protein exhibited the highest activity at 10 degrees C with a k(cat)/K(m) value of 0.87 micro m(-1) x s(-1). When the peptidyl-prolyl cis-trans isomerase activity was determined by the RNase T(1) refolding assay at 10 and 20 degrees C, the protein exhibited higher activity at 10 degrees C with a k(cat)/K(m) value of 0.50 micro m(-1) x s(-1). These k(cat)/K(m) values are lower but comparable to those of E. coli FKBP22. We propose that a FKBP family protein is involved in cold-adaptation of psychrotrophic bacteria.
Suzuki
Yutaka
Y
Department of Material and Life Science, Graduate School of Engineering, Osaka University, Japan.
Haruki
Mitsuru
M
Takano
Kazufumi
K
Morikawa
Masaaki
M
Kanaya
Shigenori
S
D000595:Amino Acid Sequence; D002384:Catalysis; D003001:Cloning, Molecular; D003080:Cold Temperature; D004247:DNA / Q000737:chemistry; D015180:Electrophoresis, Gel, Two-Dimensional; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008957:Models, Genetic; D008969:Molecular Sequence Data; D008970:Molecular Weight; D019696:Peptidylprolyl Isomerase / Q000737:chemistry; D010957:Plasmids / Q000378:metabolism; D011485:Protein Binding; D011489:Protein Denaturation; D017510:Protein Folding; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry; D006163:Ribonuclease T1 / Q000737:chemistry; D017386:Sequence Homology, Amino Acid; D020592:Shewanella / Q000378:metabolism*; D022021:Tacrolimus Binding Proteins / Q000737:chemistry*; D013696:Temperature; D013997:Time Factors
D011994:Recombinant Proteins; D004247:DNA; D006163:Ribonuclease T1; C403422:FKBP22; D022021:Tacrolimus Binding Proteins; D019696:Peptidylprolyl Isomerase