Nucleotide sequences of four variants of the K88 gene of porcine enterotoxigenic Escherichia coli

Abstract

The nucleotide sequences of four variants of the Escherichia coli K88 antigen gene, K88ab1, K88ab2, K88ac, and K88ad, have been determined. The K88ab2 and K88ac sequences have not been reported previously. The K88ab1 sequence is very similar to that determined by other workers, but the K88ad sequence differs considerably from that described in a previous report. Comparison of the amino acid sequences inferred from the gene sequences revealed certain clusters of amino acid substitutions which have been correlated with areas of potential antigenicity in the mature proteins.

Specific DNA Fragments Coding for ST1 and LT1 Toxins, and K88 (F4) Adhesin in Enterotoxigenic Escherichia coli

“…According to PARRY and ROOKE (1985) there are no differences in the first 23 N-terminal or the last 24 C-terminal amino acids between the variants. This is also consistent with the nucleotide sequences of the variants of the F4 gene published by DYKES et al (1985). They reported that all the sequence differences between the F4 proteins occur between amino acid residues 28 and 227 in the mature proteins.…”

Cloning of DNA sequences encoding foreign peptides and their expression in the K88 pili

“…Nucleotide sequence starting at the Hindll site within the 15-kilodalton protein coding sequence to the Dmi1l site downstream of the K88ac pilin gene of pAC118. The DNA sequence from the ATG to the stop codon is the same as previously published (4). The restriction sites used are underlined; the deletion introduced in pAC211 is delimited by square brackets; two linear epitopes are delimited by vertical bars; the selected insertion sites are within brackets.…”

“…In this designation, "a" refers to common antigenic determinants shared by all three serotypes, whereas "b", "c", and "d" designations refer to variable antigenic determinants. A comparison of the amino acid sequences of the various K88 pilins allowed the localization of the common and variable parts of the amino acid sequences of the pilins (4,13,26). It was assumed that conserved regions contain common antigenic determinants and that variable clusters contain variable epitopes.…”

The Three-dimensional Crystal Structure of Cholera Toxin

“…Comparison of the amino acid sequences of the A subunits of cholera (CT) and heat-labile (LT) enterotoxins(12). The LT isozyme shown…”