Characterization of the cold-adapted alpha-tubulin from the psychrophilic ciliate Euplotes focardii.
Tubulin dimers of psychrophilic organisms can polymerize into microtubules at temperatures below 4 degrees C, at which non-cold-adapted microtubules disassemble. This capacity requires specificities in the structure and/or in the posttranslational modifications of the tubulin subunits. A contribution to the knowledge of these specificities was provided by the finding that the amino acid sequence of the alpha-tubulin of the Antarctic ciliate Euplotes focardii contains substitutions that, in addition to conferring an increased hydrophobicity to the molecule, modify sites that are involved in alpha-/alpha-tubulin lateral contacts between protofilaments. At the level of the coding sequence, the alpha-tubulin gene of E. focardii revealed an A+T content appreciably higher than in its homologs in ciliates of temperate waters. This was interpreted as an adaptation to favor DNA strand separation in an environment which is energetically adverse.
Pucciarelli
Sandra
S
Dipartimento di Biologia Molecolare, Cellulare, Animale, Università di Camerino, Via F. Camerini 5, 62032 Camerino (MC), Italy.
Miceli
Cristina
C
D000222:Adaptation, Physiological; D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D000818:Animals; D000864:Antarctic Regions; D001482:Base Composition; D003001:Cloning, Molecular; D003080:Cold Temperature; D016812:Euplotes / Q000737:chemistry* / Q000502:physiology; D017125:Genes, Protozoan; D008969:Molecular Sequence Data; D011499:Protein Processing, Post-Translational; D021122:Protein Subunits; D015800:Protozoan Proteins / Q000737:chemistry*; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014404:Tubulin / Q000737:chemistry*
D021122:Protein Subunits; D015800:Protozoan Proteins; D014404:Tubulin