Metalloproteome remodeling in calprotectin-stressed Acinetobacter baumannii using chemoproteomics

ABSTRACT: The growth of bacterial pathogens is limited by nutritional immunity, where the infected host deploys metal scavenging proteins to starve the pathogen of essential transition metals. An important transition metal-sequestering protein is the Ca2+-activated S100A8-S100A9 heterotetramer, calprotectin (CP). Prior work reveals that CP induces a significant Fe- and Zn-starvation response in the Gram-negative opportunistic pathogen, Acinetobacter baumannii, in liquid culture. Here, we employ a quantitative thiol-specific chemoproteomics platform to pinpoint changes in abundance-corrected cysteine reactivity, and by extension cellular metal occupancy in metalloenzymes, that occur when A. baumannii is challenged with physiological CP in liquid culture relative to an untreated WT control. Changes in protein abundance with CP stress reveals a pronounced Zn-limitation and Fe-starvation response and reciprocal regulation of three enzymes of central carbon metabolism, including aconitase. A majority of 2645 quantifiable Cys-containing peptides that show an increase in abundance-corrected Cys reactivity (150) are derived from known Zn- and Fe-S-cluster proteins, revealing a significant decrease in metal occupancy in the proteome. Myriad cell processes are compromised by undermetalation of the metalloproteome, including enzymes that function in the TCA cycle and respiration, GTP metabolism, ribosome remodeling, tRNA charging, and proteostasis. A direct comparison of a strain lacking the candidate metallochaperone ZigA (∆zigA) with the wild-type strain reveals that the loss of ZigA is effectively silent in this assay. We conclude that CP induces a widespread, negative impact on the metalation status of the metalloproteome that results in a significant nutrient limitation response.

INSTRUMENT(S):

ORGANISM(S): Acinetobacter Baumannii (strain Atcc 17978 / Cip 53.77 / Lmg 1025 / Ncdc Kc755 / 5377)

SUBMITTER: Daniel Bak  

LAB HEAD: Eranthie Weerapana

PROVIDER: PXD067881 | Pride | 2026-04-11

REPOSITORIES: Pride