Klebsiella infections are a fast emerging health-burdening endemic, being acquired both in community and nosocomial environments. The bacterium is the aetiological agent linked to severe ailments including pneumonia, septicaemia and meningitis. In Klebsiella spp. and other Gram-negative bacteria, members of the Omp85 protein superfamily are universally distributed in the genomes. The Omp85 protein superfamily have been categorised based on shared sequence and structural characteristics with essential functions linked to protein translocation and assembly into the outer membrane (OM)
In laboratory Escherichia coli K12 strains, there are only two Omp85 proteins present – BamA &TamA. BamA is a core protein subunit of the β-barrel Assembly Machinery (BAM) complex essential in correct assembly and integration of β-barrel proteins into the OM, whilst TamA is a core protein subunit of the Translocation and Assembly Module (TAM) that acts synergistically with the BAM complex in the assembly of at least some virulence factors. Interestingly, in Klebsiella pneumoniae and other species in the genus, additional Omp85 paralogues (divergent from BamA and TamA) are conserved in the Klebsiella genome which are yet to be characterised.
We are investigating the function and structure of these uncharacterised conserved Omp85 family members, as well as BamA and TamA, using Klebsiella pneumoniae as a model. The determination of the function and structure of these uncharacterised Omp85 family members promises to reveal insights in outer membrane biogenesis and potential roles in bacterial virulence and pathogenicity of this pathogenic organism.