Zinc is the second most abundant transition metal in bacterial cells. Therefore, maintaining zinc homeostasis is critical for bacterial survival, as it requires that intracellular zinc levels be precisely regulated to meet metabolic demand while remaining below the threshold of toxicity. In Klebsiella pneumoniae, this homeostasis is primarily maintained by dedicated zinc uptake and efflux systems situated between the outer and inner membranes (Maunders et al., 2024). The bacterium also encodes a γ-class carbonic anhydrase (γ-CA), a zinc-dependent metalloenzyme that catalyzes the reversible hydration of carbon dioxide. Notably, such a high-affinity zinc-binding protein is localized in the cytoplasm. This localization raises the question of whether it plays a role beyond catalysis, potentially interacting with cellular zinc homeostasis.
To explore this possibility, we are characterizing a structural and functional characterization of γ-CA. Our approach involves recombinant expression and purification of the enzyme, coupled with structural analysis using X-ray crystallography to determine its zinc coordination geometry. In parallel, we are using assays to measure its catalytic activity.
This poster presents our progress in these studies. By integrating the resulting structural and functional data, we aim to assess the potential involvement of γ-CA in zinc homeostasis, thereby advancing our understanding of zinc metabolism in K. pneumoniae.
References:
[1] Maunders EA, Giles MW, Ganio K, Cunningham BA, Bennett-Wood V, Cole GB, Ng D, Lai CC, Neville SL, Moraes TF, McDevitt CA and Tan A (2024), “Zinc acquisition and its contribution to Klebsiella pneumoniae virulence.” Front. Cell. Infect. Microbiol. 13:1322973.