Differential Proteomics of pprI-Knockout Deinococcus radiodurans: A Label-Free Quantitative Analysis

Deinococcus radiodurans, renowned for its exceptional resistance to radiation, provides a robust model for elucidating cellular stress responses and DNA repair mechanisms. The global regulator PprI plays a pivotal role in maintaining this resilience by coordinating DNA damage repair, antioxidant defense, and metabolic reprogramming. This study employs label-free quantitative proteomics coupled with high-resolution mass spectrometry to systematically compare the proteomic profiles of pprI-knockout and wild-type D. radiodurans strains. Under stringent screening criteria, we identified 719 significantly upregulated and 281 significantly downregulated proteins in the knockout strain. Functional analysis revealed that PprI deletion disrupts homologous recombination (HR) repair, activates nucleotide excision repair (NER) and base excision repair (BER) as a compensatory mechanism, and impairs Mn/Fe homeostasis and carotenoid biosynthesis, leading to increased oxidative stress. Furthermore, PprI deficiency induces significant metabolic reprogramming, including impaired purine synthesis, compromised cell wall integrity,etc. These findings highlight PprI as a central orchestrator of multi-pathway synergies, providing critical insights into the molecular mechanisms underlying extreme radiation resistance.