Journal of Molecular Evolution

, Volume 42, Issue 5, pp 560–569

Analysis of the amino acid sequences of plant Bowman-Birk inhibitors

Authors

  • Balaji Prakash
    • Molecular Biophysics UnitIndian Institute of Science
  • S. Selvaraj
    • Molecular Biophysics UnitIndian Institute of Science
  • M. R. N. Murthy
    • Molecular Biophysics UnitIndian Institute of Science
  • Y. N. Sreerama
    • Department of Biochemistry and NutritionCentral Food Technological Research Institute
  • D. Rajagopal Rao
    • Department of Biochemistry and NutritionCentral Food Technological Research Institute
  • Lalitha R. Gowda
    • Department of Biochemistry and NutritionCentral Food Technological Research Institute
Articles

DOI: 10.1007/BF02352286

Cite this article as:
Prakash, B., Selvaraj, S., Murthy, M.R.N. et al. J Mol Evol (1996) 42: 560. doi:10.1007/BF02352286

Abstract

Plant seeds contain a large number of protease inhibitors of animal, fungal, and bacterial origin. One of the well-studied families of these inhibitors is the Bowman-Birk family(BBI). The BBIs from dicotyledonous seeds are 8K, double-headed proteins. In contrast, the 8K inhibitors from monocotyledonous seeds are single headed. Monocots also have a 16K, double-headed inhibitor. We have determined the primary structure of a Bowman-Birk inhibitor from a dicot, horsegram, by sequential edman analysis of the intact protein and peptides derived from enzymatic and chemical cleavage. The 76-residue-long inhibitor is very similar to that ofMacrotyloma axillare. An analysis of this inhibitor along with 26 other Bowman-Birk inhibitor domains (MW 8K) available in the SWISSPROT databank revealed that the proteins from monocots and dicots belong to related but distinct families. Inhibitors from monocots show larger variation in sequence. Sequence comparison shows that a crucial disulphide which connects the amino and carboxy termini of the active site loop is lost in monocots. The loss of a reactive site in monocots seems to be correlated to this. However, it appears that this disulphide is not absolutely essential for retention of inhibitory function. Our analysis suggests that gene duplication leading to a 16K inhibitor in monocots has occurred, probably after the divergence of monocots and dicots, and also after the loss of second reactive site in monocots.

Key words

Bowman-BirkInhibitorsSequence analysisMonocotyledonDicotyledonGene duplicationDolichos biflorus

Copyright information

© springer-Verlag New York Inc 1996