Identification of nucleoid associated proteins (NAPs) under oxidative stress in Staphylococcus aureus

BMC Microbiology

Research Article

Kazuya Morikawa¹  Ryosuke L. Ohniwa²  Yuri Ushijima³ 

[1] Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, 305-8575, Tsukuba, Japan;Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, 305-8575, Tsukuba, Japan;Center for Biotechnology, National Taiwan University, Taipei 10617, Taiwan, Republic of China;Graduate School of Comprehensive Human Sciences, University of Tsukuba, 1-1-1 Tennodai, 305-8575, Tsukuba, Japan;Present address: Department of Emerging Infectious Diseases, Institute of Tropical Medicine, Nagasaki University, 1-12-4 Sakamoto, 852-8523, Nagasaki, Japan;

关键词: Staphylococcus aureus;    Nucleoid-associated proteins;    Oxidative stress;   

DOI  :  10.1186/s12866-017-1114-3

 received in 2017-05-02, accepted in 2017-09-13,  发布年份 2017

来源: Springer

【 摘 要 】

BackgroundBacterial nucleoid consists of genome DNA, RNA, and hundreds of nucleoid-associated proteins (NAPs). Escherichia coli nucleoid is compacted towards the stationary phase, replacing most log-phase NAPs with the major stationary-phase nucleoid protein, Dps. In contrast, Staphylococcus aureus nucleoid sustains the fiber structures throughout the growth. Instead, the Dps homologue, MrgA, expresses under oxidative stress conditions to clump the nucleoid, but the composition of the clumped nucleoid was elusive.ResultsThe staphylococcal nucleoid under oxidative stress was isolated by sucrose gradient centrifugation, and the proteins were analyzed by liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS). We identified 299 proteins in the nucleoid under oxidative stress, including 113 csNAPs (contaminant-subtracted NAPs). Comparison with the previously identified csNAPs in log- and stationary phase indicated that one fifth of the csNAPs under oxidative stress were the constitutive nucleoid components; importantly, several factors including HU, SarA, FabZ, and ribosomes were sustained under oxidative stress. Some factors (e.g. SA1663 and SA0092/SA0093) with unknown functions were included in the csNAPs list specifically under oxidative stress condition.ConclusionNucleoid constitutively holds Hu, SarA, FabG, and ribosomal proteins even under the oxidative stress, reflecting the active functions of the clumped nucleoid, unlikely to the dormant E. coli nucleoid compacted in the stationary phase or starvation.

【 授权许可】

CC BY   
© The Author(s). 2017