title: Molecular adaptation in the ice worm, Mesenchytraeus solifugus: divergence of energetic-associated genes.
abstract: The ice worm, Mesenchytraeus solifugus, is the largest glacially obligate metazoan and among only a few metazoan species that complete their life cycle at 0 degrees C. We conducted a large-scale sequencing analysis of cDNAs isolated from ice worm anterior segments. Sequence comparisons among an available group of ice worm, arthropod, chordate, and nematode homologues suggest that ice worms encode proteins that are less bulky, are less polar, and contain fewer charged residues. Also, subunits of the catalytic F1 ATP synthase complex appear to have diverged more rapidly than other ice worm genes examined, suggesting a role in cold-temperature adaptation. Modeling of F1 ATP synthase beta and gamma subunits identified nonconservative, ice worm-specific amino acid substitutions at subunit contact sites and at sites proximal to the catalytic site.
authors.affiliation: Biology Department, 315 Penn Street, Rutgers The State University of New Jersey, Camden, NJ 08102, USA.
authors.forename: Angela H
authors.initials: AH
authors.lastname: Farrell
authors.forename: Kristi A
authors.initials: KA
authors.lastname: Hohenstein
authors.forename: Daniel H
authors.initials: DH
authors.lastname: Shain
mesh_terms: D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D000818:Animals; D000845:Annelida / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D018076:DNA, Complementary / Q000235:genetics; D004734:Energy Metabolism / Q000235:genetics*; D019143:Evolution, Molecular; D006801:Humans; D007053:Ice; D008958:Models, Molecular; D008969:Molecular Sequence Data; D020836:Protein Structure, Quaternary; D021122:Protein Subunits / Q000737:chemistry; D006180:Proton-Translocating ATPases / Q000737:chemistry / Q000235:genetics; D016415:Sequence Alignment
chemical_list: D018076:DNA, Complementary; D007053:Ice; D021122:Protein Subunits; D006180:Proton-Translocating ATPases