Purification and characterization of a novel cold-regulated protein from an ice-nucleating bacterium, Pseudomonas fluorescens KUIN-1.
The psychrotrophic ice-nucleating bacterium, Pseudomonas fluorescens KUIN-1 respond to a decrease in temperature with the induction of proteins that are classified as cold shock proteins (CSPs). We found the function of a 26-kDa protein of the CSPs in the strain KUIN-1. In strain KUIN-1, a cold shock from 18 to 4 degrees C induced the synthesis of the 26-kDa protein. By analysis with SDS-PAGE, it was then demonstrated that the 26-kDa protein was produced by the cells after treatment at 4 degrees C. The 26-kDa protein was purified to apparent homogeneity by (NH4)2SO4 precipitation and some chromatographies (QA52, phenyl Superose, Superose 12, and Mono Q). The purified 26-kDa protein is composed of 6 subunits of 26.5-kDa with a molecular mass of approximately 159-kDa according to gel filtration and SDS-PAGE. The N-terminal sequence of the 26-kDa protein was Gln-Ala-Ala-Tyr-Tyr-Pro-Ala-His-His-His-Gln- Gln-Val-Gln-Gln-His-Trp-Gly-His-His-. Specifically, 26-kDa protein of the CSPs of strain KUIN-1 was very effective in protecting the cold-labile enzyme, lactate dehydrogenase against denaturation by freezing. The characteristics of 26-kDa protein are analogous to the cold-regulated protein of the plants.
Obata
H
H
Department of Biotechnology, Faculty of Engineering, Kansai University, Osaka, Japan. obata@ipcku.kansai-u.ac.jp
Ishigaki
H
H
Kawahara
H
H
Yamade
K
K
D000222:Adaptation, Physiological; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000302:isolation & purification*; D003080:Cold Temperature; D003451:Cryoprotective Agents / Q000494:pharmacology; D005615:Freezing; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008969:Molecular Sequence Data; D008970:Molecular Weight; D011551:Pseudomonas fluorescens / Q000378:metabolism*; D013045:Species Specificity