Reduction of enterotoxic activity of Escherichia coli heat-stable enterotoxin by substitution for an asparagine residue

Keinosuke Okamoto, K. Okamoto, J. Yukitake, A. Miyama

Research output: Contribution to journalArticle

24 Citations (Scopus)

Abstract

The Escherichia coli heat-stable enterotoxins (STs) are small peptide toxins consisting of 18 (STp) or 19 (STh) amino acids. STp and STh share biologically active sequences which reside in the C-terminal 13 amino acid residues, but the role of each amino acid in the active sequences is not clear. We substituted in vivo Asp, Tyr, His, Gln, Lys, and Arg for the Asn residue at position 11 of STp by oligonucleotide-directed site-specific mutagenesis and examined the biological activities of the resulting mutants. All mutant STs reacted with both monoclonal and polyclonal antibodies, demonstrating that the amino acid substitutions at position 11 did not cause a significant change in the conformation of STp. However, the substitutions invariably caused a significant decrease in enterotoxic activities. The most remarkable decrease was observed with Asn-11 → Lys-11 and Asn-11 → Arg-11 mutations; that is, enterotoxic activity could not be detected in the culture supernatant of either of these mutant strains. These results indicate that Asn-11 of STp plays an essential role in the enterotoxic activity. The amide group and the length of side chain of Asn-11 seem to be especially important for enterotoxic activity.

Original languageEnglish
Pages (from-to)2144-2148
Number of pages5
JournalInfection and Immunity
Volume56
Issue number8
Publication statusPublished - 1988
Externally publishedYes

Fingerprint

Enterotoxins
Asparagine
Hot Temperature
Escherichia coli
Amino Acids
Amino Acid Substitution
Site-Directed Mutagenesis
Amides
Oligonucleotides
Monoclonal Antibodies
Peptides
Mutation

ASJC Scopus subject areas

  • Immunology

Cite this

Reduction of enterotoxic activity of Escherichia coli heat-stable enterotoxin by substitution for an asparagine residue. / Okamoto, Keinosuke; Okamoto, K.; Yukitake, J.; Miyama, A.

In: Infection and Immunity, Vol. 56, No. 8, 1988, p. 2144-2148.

Research output: Contribution to journalArticle

@article{59225caa93a5481ca04d8abded5915ff,
title = "Reduction of enterotoxic activity of Escherichia coli heat-stable enterotoxin by substitution for an asparagine residue",
abstract = "The Escherichia coli heat-stable enterotoxins (STs) are small peptide toxins consisting of 18 (STp) or 19 (STh) amino acids. STp and STh share biologically active sequences which reside in the C-terminal 13 amino acid residues, but the role of each amino acid in the active sequences is not clear. We substituted in vivo Asp, Tyr, His, Gln, Lys, and Arg for the Asn residue at position 11 of STp by oligonucleotide-directed site-specific mutagenesis and examined the biological activities of the resulting mutants. All mutant STs reacted with both monoclonal and polyclonal antibodies, demonstrating that the amino acid substitutions at position 11 did not cause a significant change in the conformation of STp. However, the substitutions invariably caused a significant decrease in enterotoxic activities. The most remarkable decrease was observed with Asn-11 → Lys-11 and Asn-11 → Arg-11 mutations; that is, enterotoxic activity could not be detected in the culture supernatant of either of these mutant strains. These results indicate that Asn-11 of STp plays an essential role in the enterotoxic activity. The amide group and the length of side chain of Asn-11 seem to be especially important for enterotoxic activity.",
author = "Keinosuke Okamoto and K. Okamoto and J. Yukitake and A. Miyama",
year = "1988",
language = "English",
volume = "56",
pages = "2144--2148",
journal = "Infection and Immunity",
issn = "0019-9567",
publisher = "American Society for Microbiology",
number = "8",

}

TY - JOUR

T1 - Reduction of enterotoxic activity of Escherichia coli heat-stable enterotoxin by substitution for an asparagine residue

AU - Okamoto, Keinosuke

AU - Okamoto, K.

AU - Yukitake, J.

AU - Miyama, A.

PY - 1988

Y1 - 1988

N2 - The Escherichia coli heat-stable enterotoxins (STs) are small peptide toxins consisting of 18 (STp) or 19 (STh) amino acids. STp and STh share biologically active sequences which reside in the C-terminal 13 amino acid residues, but the role of each amino acid in the active sequences is not clear. We substituted in vivo Asp, Tyr, His, Gln, Lys, and Arg for the Asn residue at position 11 of STp by oligonucleotide-directed site-specific mutagenesis and examined the biological activities of the resulting mutants. All mutant STs reacted with both monoclonal and polyclonal antibodies, demonstrating that the amino acid substitutions at position 11 did not cause a significant change in the conformation of STp. However, the substitutions invariably caused a significant decrease in enterotoxic activities. The most remarkable decrease was observed with Asn-11 → Lys-11 and Asn-11 → Arg-11 mutations; that is, enterotoxic activity could not be detected in the culture supernatant of either of these mutant strains. These results indicate that Asn-11 of STp plays an essential role in the enterotoxic activity. The amide group and the length of side chain of Asn-11 seem to be especially important for enterotoxic activity.

AB - The Escherichia coli heat-stable enterotoxins (STs) are small peptide toxins consisting of 18 (STp) or 19 (STh) amino acids. STp and STh share biologically active sequences which reside in the C-terminal 13 amino acid residues, but the role of each amino acid in the active sequences is not clear. We substituted in vivo Asp, Tyr, His, Gln, Lys, and Arg for the Asn residue at position 11 of STp by oligonucleotide-directed site-specific mutagenesis and examined the biological activities of the resulting mutants. All mutant STs reacted with both monoclonal and polyclonal antibodies, demonstrating that the amino acid substitutions at position 11 did not cause a significant change in the conformation of STp. However, the substitutions invariably caused a significant decrease in enterotoxic activities. The most remarkable decrease was observed with Asn-11 → Lys-11 and Asn-11 → Arg-11 mutations; that is, enterotoxic activity could not be detected in the culture supernatant of either of these mutant strains. These results indicate that Asn-11 of STp plays an essential role in the enterotoxic activity. The amide group and the length of side chain of Asn-11 seem to be especially important for enterotoxic activity.

UR - http://www.scopus.com/inward/record.url?scp=0023721826&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0023721826&partnerID=8YFLogxK

M3 - Article

C2 - 3294186

AN - SCOPUS:0023721826

VL - 56

SP - 2144

EP - 2148

JO - Infection and Immunity

JF - Infection and Immunity

SN - 0019-9567

IS - 8

ER -