Variation in Length and Sequence of Porin (OMPP2) Alleles of Noncapsulate Haemophilus-Influenzae

Ken J. Forbes, K D BRUCE, A BALL, Thomas Hugh Pennington

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Length variations of Haemophilus influenzae outer membrane porin protein P2 were found at the DNA and protein levels, notably in non-capsulate strains. Protein length, measured by SDS-polyacrylamide gel electrophoresis, was found to correlate with the length of the gene, measured by polymerase chain reaction amplification, and ranged from 35-42 kDa and 970-1090 nucleotides, respectively. This represents a length variation of some 15%. The genetic location of these variations was studied by restriction enzyme mapping 10 of the non-capsulate strains revealing further polymorphisms at the DNA level. All 10 strains were distinct and differed from a type b strain. The conservation and assortment of the different restriction sites in the alleles is discussed in relation to the very great diversity previously described for this protein and of the whole genome itself in non-capsulate strains. The roles of selection, horizontal gene transfer, and transformation in generating this diversity are discussed.

Original languageEnglish
Pages (from-to)2107-2112
Number of pages6
JournalMolecular Microbiology
Issue number15
Publication statusPublished - Aug 1992


  • outer-membrane protein
  • nontypable Hemophilus-Influenzae
  • gene
  • P2
  • epitopes
  • profiles
  • cloning
  • clones
  • DNA


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