Saito Mak A, McIlvin Matthew R
Marine Chemistry and Geochemistry Department, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, United States.
Metallomics. 2025 Jul 9;17(7). doi: 10.1093/mtomcs/mfaf023.
Pseudomonas aeruginosa is a major contributor to human infections and is widely distributed in the environment. Its ability for growth under aerobic and anaerobic conditions provides adaptability to environmental changes and in confronting immune responses. We applied native 2-dimensional metalloproteomics to P. aeruginosa to examine how use of iron within the metallome responds to oxic and anoxic conditions. Analyses revealed four iron peaks comprised of metalloproteins with synergistic functions, including (1) respiratory and metabolic enzymes, (2) oxidative stress response enzymes, (3) DNA synthesis and nitrogen assimilation enzymes, and (4) denitrification enzymes and related copper enzymes. Fe Peaks were larger under anoxic conditions, consistent with increased iron demand due to anaerobic metabolism and with the denitrification peak absent under oxic conditions. Three ferritins co-eluted with the first and third iron peaks, localizing iron storage with these functions. Several enzymes were more abundant at low oxygen, including alkylhydroperoxide reductase C that deactivates organic radicals produced by denitrification, all three classes of ribonucleotide reductases (including monomer and oligomer forms), ferritin (increasing in ratio relative to bacterioferritin), and denitrification enzymes. Superoxide dismutase and homogentisate 1,2-dioxygenase were more abundant at high oxygen. Several Fe Peaks contained iron metalloproteins that co-eluted earlier than their predicted size, implying additional protein-protein interactions and suggestive of cellular organization that contributes to iron prioritization in Pseudomonas with its large genome and flexible metabolism. This study characterized the iron metalloproteome of one of the more complex prokaryotic microorganisms, attributing enhanced iron use under anaerobic denitrifying metabolism to its specific metalloprotein constituents.
铜绿假单胞菌是导致人类感染的主要病菌，广泛分布于环境中。它在有氧和无氧条件下均能生长，这使其能够适应环境变化并应对免疫反应。我们将天然二维金属蛋白质组学应用于铜绿假单胞菌，以研究金属蛋白质组中铁的利用如何响应有氧和无氧条件。分析揭示了四个由具有协同功能的金属蛋白组成的铁峰，包括：（1）呼吸和代谢酶；（2）氧化应激反应酶；（3）DNA合成和氮同化酶；（4）反硝化酶和相关铜酶。铁峰在无氧条件下更大，这与厌氧代谢导致的铁需求增加以及有氧条件下不存在反硝化峰一致。三种铁蛋白与第一和第三个铁峰共洗脱，将铁储存定位到这些功能中。几种酶在低氧条件下更为丰富，包括使反硝化产生的有机自由基失活的烷基过氧化氢还原酶C、所有三类核糖核苷酸还原酶（包括单体和寡聚体形式）、铁蛋白（相对于细菌铁蛋白比例增加）和反硝化酶。超氧化物歧化酶和尿黑酸1,2-双加氧酶在高氧条件下更为丰富。几个铁峰包含的铁金属蛋白比其预测大小更早共洗脱，这意味着存在额外的蛋白质-蛋白质相互作用，并暗示了细胞组织有助于在具有大基因组和灵活代谢的铜绿假单胞菌中对铁进行优先排序。这项研究表征了一种较为复杂的原核微生物的铁金属蛋白质组，将厌氧反硝化代谢下铁利用的增强归因于其特定的金属蛋白成分。
