RT Journal
A1 Saunders, Neil F.W.
A1 Thomas, Torsten
A1 Curmi, Paul M.G.
A1 Mattick, John S.
A1 Kuczek, Elizabeth
A1 Slade, Rob
A1 Davis, John
A1 Franzmann, Peter D.
A1 Boone, David
A1 Rusterholtz, Karl
A1 Feldman, Robert
A1 Gates, Chris
A1 Bench, Shellie
A1 Sowers, Kevin
A1 Kadner, Kristen
A1 Aerts, Andrea
A1 Dehal, Paramvir
A1 Detter, Chris
A1 Glavina, Tijana
A1 Lucas, Susan
A1 Richardson, Paul
A1 Larimer, Frank
A1 Hauser, Loren
A1 Land, Miriam
A1 Cavicchioli, Ricardo
T1 Mechanisms of Thermal Adaptation Revealed From the Genomes of the
 Antarctic Archaea Methanogenium frigidum and Methanococcoides
 burtonii
JF Genome Research 
JO Genome Research 
YR 2003 
FD July 01 
VO 13 
IS 7 
SP 1580 
OP 1588 
DO 10.1101/gr.1180903 
UL http://genome.cshlp.org/content/13/7/1580.abstract 
AB We generated draft genome sequences for two cold-adapted Archaea,
 Methanogenium frigidum and Methanococcoides burtonii, to
 identify genotypic characteristics that distinguish them from Archaea
 with a higher optimal growth temperature (OGT). Comparative genomics revealed
 trends in amino acid and tRNA composition, and structural features of
 proteins. Proteins from the cold-adapted Archaea are characterized by
 a higher content of noncharged polar amino acids, particularly Gln and Thr and
 a lower content of hydrophobic amino acids, particularly Leu. Sequence data
 from nine methanogen genomes (OGT 15°–98°C) were used to
 generate 1111 modeled protein structures. Analysis of the models from the
 cold-adapted Archaea showed a strong tendency in the
 solvent-accessible area for more Gln, Thr, and hydrophobic residues and fewer
 charged residues. A cold shock domain (CSD) protein (CspA homolog) was
 identified in M. frigidum, two hypothetical proteins with CSD-folds
 in M. burtonii, and a unique winged helix DNA-binding domain protein
 in M. burtonii. This suggests that these types of nucleic acid
 binding proteins have a critical role in cold-adapted Archaea.
 Structural analysis of tRNA sequences from the Archaea indicated that
 GC content is the major factor influencing tRNA stability in
 hyperthermophiles, but not in the psychrophiles, mesophiles or moderate
 thermophiles. Below an OGT of 60°C, the GC content in tRNA was largely
 unchanged, indicating that any requirement for flexibility of tRNA in
 psychrophiles is mediated by other means. This is the first time that
 comparisons have been performed with genome data from Archaea
 spanning the growth temperature extremes from psychrophiles to
 hyperthermophiles.