Molecular Diversity

, Volume 10, Issue 4, pp 567–573

Structure based studies of the adaptive diversification process of congerins

  • Tsuyoshi Shirai
  • Clara Shionyu-Mitsuyama
  • Tomohisa Ogawa
  • Koji Muramoto

DOI: 10.1007/s11030-006-9030-8

Cite this article as:
Shirai, T., Shionyu-Mitsuyama, C., Ogawa, T. et al. Mol Divers (2006) 10: 567. doi:10.1007/s11030-006-9030-8


The isoforms of a fish galectin, congerins I and II, have several features that make them suitable for a study of accelerated process of molecular diversification based on 3D structures: They have been generated by a gene duplication, and still maintain 47% amino acid sequence identity to each other. Their genes show very high KA/KS ratio, and are though to be components of fish defense system. The crystal systems for a high-resolution analysis are known for both proteins. A series of works with biochemistry, molecular biology, and X-ray crystallography techniques have suggested that the two proteins might have evolved under differential selection pressures. Congerin I appeared to be a stabilized version of galectin-1. Congerin II was shown to be adapted to a new carbohydrate-ligand. The 3D structures of the wild type and mutant proteins have revealed the probable cause and consequence of the selection pressure responsible for the diversification of congerins.

Key words

crystal structuregalectinaccelerated evolutionbioinformatics



three dimensional


2-N-morpholino ethane sulfonic acid


protein data bank


maximum likelihood


maximum parsimony


standard error


polymerase chain reaction

Copyright information

© Springer Science+Business Media, Inc. 2006

Authors and Affiliations

  • Tsuyoshi Shirai
    • 1
    • 2
  • Clara Shionyu-Mitsuyama
    • 3
  • Tomohisa Ogawa
    • 4
  • Koji Muramoto
    • 4
  1. 1.Department of BioscienceNagahama Institute of Bio-Science and TechnologyNagahama, SigaJapan
  2. 2.JST-BIRDNagahama, SigaJapan
  3. 3.Institute for Protein ResearchOsaka UniversitySuitaJapan
  4. 4.Department of Biomolecular Science, Graduate School of Life SciencesTohoku UniversitySendaiJapan