Amino-acid residues involved in biological functions of the cytolytic enterotoxin from Aeromonas hydrophila

M. R. Ferguson, Xin Jing Xu, C. W. Houston, J. W. Peterson, A. K. Chopra

Research output: Contribution to journalArticle

8 Scopus citations

Abstract

Some amino acid (aa) residues within the cytolytic enterotoxin (Act) of Aeromonas hydrophila essential for biological activity were identified. Act is a 52-kDa polypeptide, possessing hemolytic, cytotoxic and enterotoxic activities. By deletion analysis, generation of anti-peptide Ab, and site-directed mutagenesis we showed that two regions in Act (aa 245-274 and 361-405) were very important for biological functions. As shown by competitive inhibition assays, peptide 2 (aa 245-274) blocked cytotoxic activity of Act, and aa Tyr256, Trp270 and Gly274 were essential for cytotoxicity. Within peptide 3 (aa 361-405), Trp394 and Trp396 were important for biological activities. Mutations in other regions of the toxin (e.g., Gly169, Asp 170, Gly171, Trp172, Asn177,178, Asp179 and His144,209,355) also decreased biological activity. The reactivity of these mutant toxins with Ab in immunoblots was not altered. Data reported in this study suggested the role of some aa residues in biological function(s) of Act.

Original languageEnglish (US)
Pages (from-to)79-83
Number of pages5
JournalGene
Volume156
Issue number1
DOIs
StatePublished - Apr 14 1995

Keywords

  • Deletion analysis
  • anti-peptide antibodies
  • immunoblot analysis
  • sequencing
  • site-directed mutagenesis

ASJC Scopus subject areas

  • Genetics

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