Poster Presentation The 43rd Lorne Conference on Protein Structure and Function 2018

Structure and function of the OmpK37 porin from the outer membrane of Klebsiella pneumoniae (#266)

Andrea Rocker 1 , Rhys Grinter 1 , Jonathan J Wilksch 2 , Mark Davies 2 , Tieli Zhou 3 , Richard A Strugnell 2 , Trevor Lithgow 1
  1. Infection and Immunity Program, Department of Microbiology, Monash University, Melbourne, Australia
  2. Department of Microbiology & Immunology, University of Melbourne, Melbourne, Australia
  3. Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Whenzou, China

Porins are bacterial outer membrane proteins which facilitate the diffusion of small hydrophilic molecules across the lipid membrane. In Klebsiella pneumoniae, two highly abundant major porins, OmpK35 and OmpK36, are responsible for general nutrient import, but have also been shown to allow the passage of various antibiotics, in particular β-lactams including carbapenems. Hence, as a mechanism to decrease antimicrobial influx, multidrug resistant clinical isolates often lack one or both major porins. To compensate for the simultaneous decrease in nutrient diffusion and waste efflux, alternative porins are commonly upregulated.

As the effectiveness of antimicrobial treatment is directly affected by the pore properties of the expressed porins, we investigate OmpK37, one of the alternative porins of K. pneumoniae. Previous studies indicate that expression of OmpK37 is variable and might be increased in strains deficient in the major porins. We perform X-ray protein crystallography and antibiotic sensitivity tests to compare the alternative porin OmpK37 with the major porins OmpK35 and OmpK36. Together, these experiments help to elucidate the contribution of this porin family to the rise of porin-deficient, drug-resistant K. pneumoniae isolates.