biostudies-literatureUnknownOsterberg MKNIAID NIH HHSNIGMS NIH HHSThe 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 S100A8-S100A9 heterotetramer, calprotectin (CP). Prior work reveals that CP induces a significant Zn- and Fe-starvation response in the Gram-negative opportunistic pathogen, <i>Acinetobacter baumannii</i>, in liquid culture. Here, we employ a quantitative chemoproteomics platform to pinpoint changes in abundance-corrected cysteine reactivity, and by extension cellular metal occupancy in metalloenzymes, that occur when <i>A. baumannii</i> is challenged with physiological CP in liquid culture relative to an untreated WT control. Changes in protein abundanbioRxiv : the preprint server for biology2025.09.16.676631https://www.ebi.ac.uk/biostudies/studies/S-EPMC12458113biostudies-literatureExploring metalloproteome remodeling in calprotectin-stressed &lt;i&gt;Acinetobacter baumannii&lt;/i&gt; using chemoproteomics.PMC12458113R01 AI127793R35 GM134964R35 GM118157T32 GM131994R01 AI101171Bak DWAndreini CGiedroc DPTrinidad JCAkizuki TWeerapana EOsterberg MKCornish PVChazin WJCritchlow JMSkaar EPfalseExploring metalloproteome remodeling in calprotectin-stressed &lt;i&gt;Acinetobacter baumannii&lt;/i&gt; using chemoproteomics.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 S100A8-S100A9 heterotetramer, calprotectin (CP). Prior work reveals that CP induces a significant Zn- and Fe-starvation response in the Gram-negative opportunistic pathogen, <i>Acinetobacter baumannii</i>, in liquid culture. Here, we employ a quantitative chemoproteomics platform to pinpoint changes in abundance-corrected cysteine reactivity, and by extension cellular metal occupancy in metalloenzymes, that occur when <i>A. baumannii</i> is challenged with physiological CP in liquid culture relative to an untreated WT control. Changes in protein abundan2025-01-01T00:00:00Z2025 Sep2026-06-05T03:12:18.373Z2026-06-05T03:06:52.821ZS-EPMC124581134100087110.1101/2025.09.16.676631