A Novel H-NS-like Protein from an Antarctic Psychrophilic Bacterium Reveals a Crucial Role for the N-terminal Domain in Thermal Stability*

• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Antarctic; Antarc*; Antarctica; Siberia
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.534.6730; http://www.genomed-dna.com/literatur/Star/18754.pdf

We describe here new members of the H-NS protein family identified in a psychrotrophic Acinetobacter spp. bacterium collected in Siberia and in a psychrophilic Psychrobacter spp. bacterium collected in Antarctica. Both are phylogenetically closely related to the HvrA and SPB Rhodobacter transcriptional regulators. Their amino acid sequence shares 40 % identity, and their pre-dicted secondary structure displays a structural and functional organization in two modules similar to that of H-NS in Escherichia coli. Remarkably, the Acineto-bacter protein fully restores to the wild-type H-NS-de-pendent phenotypes, whereas the Psychrobacter protein is no longer able to reverse the effects of H-NS defi-ciency in an E. coli mutant strain above 30 °C. Moreover, in vitro experiments demonstrate that the ability of the