Departamento de Ciência e Tecnologia Agroindustrial, Universidade Federal de Pelotas, Pelotas, RS, Brazil.
Central Science Laboratory, University of Tasmania, Hobart, Tasmania, Australia.
Res Microbiol. 2023 Jun;174(5):104061. doi: 10.1016/j.resmic.2023.104061. Epub 2023 Apr 11.
In this study a data dependent acquisition label-free based proteomics approach was used to identify pH-dependent proteins that respond in a growth phase independent manner in Campylobacter jejuni reference strain NCTC 11168. NCTC 11168 was grown within its pH physiological normal growth range (pH 5.8, 7.0 and 8.0, μ = ∼0.5 h) and exposed to pH 4.0 shock for 2 h. It was discovered that gluconate 2-dehydrogenase GdhAB, NssR-regulated globins Cgb and Ctb, cupin domain protein Cj0761, cytochrome c protein CccC (Cj0037c), and phosphate-binding transporter protein PstB all show acidic pH dependent abundance increases but are not activated by sub-lethal acid shock. Glutamate synthase (GLtBD) and the MfrABC and NapAGL respiratory complexes were induced in cells grown at pH 8.0. The response to pH stress by C. jejuni is to bolster microaerobic respiration and at pH 8.0 this is assisted by accumulation of glutamate the conversion of which could bolster fumarate respiration. The pH dependent proteins linked to growth in C. jejuni NCTC 11168 aids cellular energy conservation maximising growth rate and thus competitiveness and fitness.
在这项研究中，采用了一种基于数据依赖采集的无标签蛋白质组学方法来鉴定 pH 依赖性蛋白，这些蛋白以与生长阶段无关的方式响应弯曲杆菌参考菌株 NCTC 11168 的生长。NCTC 11168 在其生理 pH 正常生长范围内（pH5.8、7.0 和 8.0，μ∼0.5 h）生长，并暴露于 pH4.0 冲击 2 h。研究发现，葡萄糖酸 2-脱氢酶 GdhAB、NssR 调节的球蛋白 Cgb 和 Ctb、cupin 结构域蛋白 Cj0761、细胞色素 c 蛋白 CccC（Cj0037c）和磷酸盐结合转运蛋白 PstB 均表现出酸性 pH 依赖性丰度增加，但不受亚致死酸冲击激活。谷氨酸合酶（GLtBD）和 MfrABC 和 NapAGL 呼吸复合物在 pH8.0 下生长的细胞中被诱导。弯曲杆菌对 pH 应激的反应是增强微需氧呼吸，在 pH8.0 下，这得益于谷氨酸的积累，其转化可以增强延胡索酸呼吸。与弯曲杆菌 NCTC 11168 生长相关的 pH 依赖性蛋白有助于细胞能量的节约，从而最大限度地提高生长速度和竞争力以及适应性。
