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 language | English |
|---|---|
| Pages (from-to) | 2144-2148 |
| Number of pages | 5 |
| Journal | Infection and Immunity |
| Volume | 56 |
| Issue number | 8 |
| Publication status | Published - 1988 |
| Externally published | Yes |
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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 journal › Article
}
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.
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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 -