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CspB and CspL, thermostable cold‐shock proteins from Thermotoga maritima
Author(s) -
Phadtare Sangita,
Hwang Jihwan,
Severinov Konstantin,
Inouye Masayori
Publication year - 2003
Publication title -
genes to cells
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.912
H-Index - 115
eISSN - 1365-2443
pISSN - 1356-9597
DOI - 10.1046/j.1365-2443.2003.00675.x
Subject(s) - thermotoga maritima , rna polymerase , biology , cold shock domain , transcription (linguistics) , escherichia coli , rna , biochemistry , nucleic acid , polymerase , microbiology and biotechnology , dna , gene , linguistics , philosophy
Background: Cold‐shock proteins (Csps) are important for cellular adaptation to low temperature. Csps help cells adapt to low‐temperature growth through their RNA‐binding and nucleic acid melting abilities, which lead to anti‐termination of transcription. Results: We studied the two most thermostable Csps known to date, Tm CspB and Tm CspL from Thermotoga maritima , a hyperthermophilic eubacterium for which no cold‐shock response has been demonstrated so far. For comparison, we used a well‐characterized Escherichia coli CspE protein. Tm CspB and Tm CspL are able to bind RNA at both low and high temperatures. They are also able to ‘melt’ nucleic acids secondary structures and as a result decrease E. coli RNA polymerase transcription termination in vivo and E. coli and T. maritima RNA polymerases transcription termination in vitro . Over‐expression of Tm Csps allowed E. coli cold‐sensitive mutant cells to acclimate to the low temperatures of 15 °C. Conclusions: Tm CspB and Tm CspL (i) are able to perform essential functions of E. coli Csps in vitro and in vivo , 50–65 °C below the temperature optimum of T. maritima and (ii) can anti‐terminate transcription by T. maritima RNA polymerase at 55 °C, the lower limit of temperature range for growth of T. maritima . We propose that the observed properties of Tm Csps are physiologically relevant and that Tm Csps are important for adaptation of T. maritima to physiologically low temperatures.