The genome sequence of Psychrobacter arcticus 273-4, a psychroactive Siberian permafrost bacterium, reveals mechanisms for adaptation to low-temperature growth.
Psychrobacter arcticus strain 273-4, which grows at temperatures as low as -10 degrees C, is the first cold-adapted bacterium from a terrestrial environment whose genome was sequenced. Analysis of the 2.65-Mb genome suggested that some of the strategies employed by P. arcticus 273-4 for survival under cold and stress conditions are changes in membrane composition, synthesis of cold shock proteins, and the use of acetate as an energy source. Comparative genome analysis indicated that in a significant portion of the P. arcticus proteome there is reduced use of the acidic amino acids and proline and arginine, which is consistent with increased protein flexibility at low temperatures. Differential amino acid usage occurred in all gene categories, but it was more common in gene categories essential for cell growth and reproduction, suggesting that P. arcticus evolved to grow at low temperatures. Amino acid adaptations and the gene content likely evolved in response to the long-term freezing temperatures (-10 degrees C to -12 degrees C) of the Kolyma (Siberia) permafrost soil from which this strain was isolated. Intracellular water likely does not freeze at these in situ temperatures, which allows P. arcticus to live at subzero temperatures.
Center for Microbial Ecology, Michigan State University, East Lansing, Michigan 48824-1325, USA. hlayala@hpcf.upr.edu
Héctor L
HL
Ayala-del-Río
Patrick S
PS
Chain
Joseph J
JJ
Grzymski
Monica A
MA
Ponder
Natalia
N
Ivanova
Peter W
PW
Bergholz
Genevive
G
Di Bartolo
Loren
L
Hauser
Miriam
M
Land
Corien
C
Bakermans
Debora
D
Rodrigues
Joel
J
Klappenbach
Dan
D
Zarka
Frank
F
Larimer
Paul
P
Richardson
Alison
A
Murray
Michael
M
Thomashow
James M
JM
Tiedje
D003080:Cold Temperature; D004269:DNA, Bacterial / Q000737:chemistry* / Q000235:genetics*; D005615:Freezing; D016680:Genome, Bacterial; D008969:Molecular Sequence Data; D044096:Psychrobacter / Q000235:genetics* / Q000302:isolation & purification / Q000502:physiology; D017422:Sequence Analysis, DNA; D012800:Siberia; D012988:Soil Microbiology
D004269:DNA, Bacterial