Back to Search
Start Over
A Novel H-NS-like Protein from an Antarctic Psychrophilic Bacterium Reveals a Crucial Role for the N-terminal Domain in Thermal Stability
- Source :
- Journal of Biological Chemistry. 278:18754-18760
- Publication Year :
- 2003
- Publisher :
- Elsevier BV, 2003.
-
Abstract
- 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 predicted secondary structure displays a structural and functional organization in two modules similar to that of H-NS in Escherichia coli. Remarkably, the Acinetobacter protein fully restores to the wild-type H-NS-dependent phenotypes, whereas the Psychrobacter protein is no longer able to reverse the effects of H-NS deficiency in an E. coli mutant strain above 30 degrees C. Moreover, in vitro experiments demonstrate that the ability of the Psychrobacter H-NS protein to bind curved DNA and to form dimers is altered at 37 degrees C. The construction of hybrid proteins containing the N- or the C-terminal part of E. coli H-NS fused to the C- or N-terminal part of the Psychrobacter protein demonstrates the role of the N-terminal domain in this process. Finally, circular dichroism analysis of purified H-NS proteins suggests that, as compared with the E. coli and Acinetobacter proteins, the alpha-helical domain displays weaker intermolecular interactions in the Psychrobacter protein, which may account for the low thermal stability observed at 37 degrees C.
- Subjects :
- Circular dichroism
Hot Temperature
Protein family
Molecular Sequence Data
Antarctic Regions
Rhodobacter sphaeroides
medicine.disease_cause
Biochemistry
Protein Structure, Secondary
Rhodobacter capsulatus
Structure-Activity Relationship
Bacterial Proteins
Drug Stability
Escherichia coli
medicine
Amino Acid Sequence
Psychrobacter
Psychrophile
Molecular Biology
Peptide sequence
Protein secondary structure
Rhodobacter
Acinetobacter
biology
Circular Dichroism
DNA
Cell Biology
biology.organism_classification
Cold Temperature
DNA-Binding Proteins
Siberia
Dimerization
Sequence Alignment
Gammaproteobacteria
Subjects
Details
- ISSN :
- 00219258
- Volume :
- 278
- Database :
- OpenAIRE
- Journal :
- Journal of Biological Chemistry
- Accession number :
- edsair.doi.dedup.....589da9015092df7efb0fd9398aad199b