Comparative Complete Genome Sequence Analysis of the Amino Acid Replacements Responsible for the Thermostability of Corynebacterium efficiens

  1. Yousuke Nishio1,
  2. Yoji Nakamura2,
  3. Yutaka Kawarabayasi3,4,
  4. Yoshihiro Usuda1,
  5. Eiichiro Kimura1,
  6. Shinichi Sugimoto1,
  7. Kazuhiko Matsui1,
  8. Akihiko Yamagishi5,
  9. Hisashi Kikuchi3,
  10. Kazuho Ikeo2, and
  11. Takashi Gojobori2,6
  1. 1 Fermentation & Biotechnology Laboratories, Ajinomoto Co., Inc., Kawasaki, Kanagawa 210-8681, Japan
  2. 2 Center for Information Biology and DNA Data Bank of Japan, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan
  3. 3 National Institute of Technology and Evaluation, Shibuya, Tokyo 151-0066, Japan
  4. 4 ICMB, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8566, Japan
  5. 5 Department of Molecular Biology, Tokyo University of Pharmacy and Life Science, Hachioji, Tokyo 192-0392, Japan

Abstract

Corynebacterium efficiens is the closest relative of Corynebacterium glutamicum, a species widely used for the industrial production of amino acids. C. efficiens but not C. glutamicum can grow above 40°C. We sequenced the complete C. efficiens genome to investigate the basis of its thermostability by comparing its genome with that of C. glutamicum. The difference in GC content between the species was reflected in codon usage and nucleotide substitutions. Our comparative genomic study clearly showed that there was tremendous bias in amino acid substitutions in all orthologous ORFs. Analysis of the direction of the amino acid substitutions suggested that three substitutions are important for the stability of the C. efficiens proteins: from lysine to arginine, serine to alanine, and serine to threonine. Our results strongly suggest that the accumulation of these three types of amino acid substitutions correlates with the acquisition of thermostability and is responsible for the greater GC content of C. efficiens.

Footnotes

  • [Supplemental material is available online at www.genome.org. The sequence data from this study have been submitted to DDBJ/EMBL/GenBank under accession nos. BA000035, and AP005214–AP005224.]

  • Article and publication are at http://www.genome.org/cgi/doi/10.1101/gr.1285603.

  • 6 Corresponding author. E-mail tgojobor{at}genes.nig.ac.jp; FAX 81-559-81-6848.

    • Accepted April 25, 2003.
    • Received March 4, 2003.
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