Characterization of cold-shock protein A of Antarctic Streptomyces sp. AA8321.
Polar organisms should have mechanisms to survive the extremely cold environment. Four genes encoding cold-shock proteins, which are small, cold-induced bacterial proteins, have been cloned from the Antarctic bacterium Streptomyces sp. AA8321. Since the specific functions of any polar bacterial or Streptomyces cold-shock proteins have not yet been determined, we examined the role of cold-shock protein A from Streptomyces sp. AA8321 (CspA(St)). Gel filtration chromatography showed that purified CspA(St) exists as a homodimer under physiological conditions, and gel shift assays showed that it binds to single-stranded, but not double-stranded, DNA. Overexpression of CspA(St) in Escherichia coli severely impaired the ability of the host cells to form colonies, and the cells developed an elongated morphology. Incorporation of a deoxynucleoside analogue, 5-bromo-2'-deoxyuridine, into newly synthesized DNA was also drastically diminished in CspA(St)-overexpressing cells. These results suggest that CspA(St) play a role in inhibition of DNA replication during cold-adaptation.
Kim
Min-Jung
MJ
Department of Molecular Biology, Sejong University, 98 Gunjadong, Kwangjin-gu, Seoul, 143-747, Korea.
Lee
Yoo Kyung
YK
Lee
Hong Kum
HK
Im
Hana
H
D000222:Adaptation, Physiological; D000595:Amino Acid Sequence; D000864:Antarctic Regions; D001110:Arctic Regions; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D001973:Bromodeoxyuridine / Q000378:metabolism; D002852:Chromatography, Ion Exchange; D003001:Cloning, Molecular; D003080:Cold Temperature; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D005798:Genes, Bacterial; D016415:Sequence Alignment; D021241:Spectrometry, Mass, Electrospray Ionization; D013302:Streptomyces / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic
D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; C062260:cold shock protein CS7.4, Bacteria; D001973:Bromodeoxyuridine