Organization of the H. influenzae fhu locus and comparison of the fhu loci in H. influenzae, A. pleuropneumoniae and E. coli. The nontypeable H. influenzae strain R2846 fhu locus consists of 4 genes: 1) r2846.1777 encodes a protein with significant homology to TonB-dependent outer membrane proteins; 2) fhuB (r2846.1775) encodes a putative periplasmic substrate binding protein; 3) fhuC and fhuD (r2846.1773 and r2846.1774) encode putative cytoplasmic membrane permeases. Percentage identities (I) and similarities (S) are shown for pairwise comparisons of the FhuB, FhuC and FhuD proteins of nontypeable H. influenzae strain R2846 with the homologous proteins of Actinobacillus pleuropneumoniae strain 4074 (GenBack Accession No. AF351135) and Escherichia coli K12 substrain MG1655 (GenBack Accession No. U00096). There was no significant homology between the FhuA protein of NTHi strain R2846 and those of either A. pleuropneumoniae or E. coli. The product of orf5 (r2846.1778) has homology to a transposon integrase, and the gene appears not to be transcriptionally linked to the fhu gene cluster.
Morton et al. BMC Microbiology 2010 10:113 doi:10.1186/1471-2180-10-113