title: Proteomic analysis on the antibacterial activity of a Ru(II) complex against Streptococcus pneumoniae.
abstract: Streptococcus pneumoniae is a Gram-positive pathogen that causes a variety of infection diseases in human. In this project, we determined the antibacterial activity of a Ru(II) complex X-03 against S. pneumoniae in vitro, by comparing its toxicity to host cells A549 and HBE. We performed two-dimensional gel electrophoresis (2-DE)-based proteomic analysis to characterize the protein alterations in S. pneumoniae after treatment with X-03. In total, 50 proteins exhibiting significant differential expressions were identified. RT-PCR was used to confirm the expression differences for selected proteins. Bioinformatics analysis on the proteomic alterations suggested that Ru(II) complex X-03 may obstruct bacterial fatty acid synthesis and oxidation-reduction process to suppress the growth of S. pneumoniae. Metal-uptake experiments revealed that iron-acquisition pathway in the bacterium may be interfered by X-03. These results provide useful clues for further investigations on the mechanism of the antibacterial action of metal compounds.
  
  
  CONCLUSIONS
  The appearance of bacterial strains with broad antibiotic resistance is becoming an alarming global health concern. The development of novel efficient antibacterial compound is urgently needed. In the present study, we found that Ru(II) complex X-03 has a significant antibacterial activity and applied proteomic technology combined with bioinformatics analysis to investigate its antimicrobial mechanism in S. pneumoniae. Many proteins were found to be dysregulated, implicating that X-03 may affect various molecular pathways leading to the inhibition of bacterial growth. Metal-uptake experiments demonstrated that X-03 treatment reduced the iron content in the bacterium, suggesting the interference with iron acquisition systems by the complex. This disturbance in iron acquisition may directly or indirectly induce the proteomic response that involved many pathways. In addition, X-03 could selectively suppress Gram-positive bacteria but execute less cytotoxicity to Gram-negative bacteria, with almost no effect on human cells, implicating its potential to be developed as a specific antimicrobial agent. These results provide useful information for further investigations on the mechanism of the antibacterial action of metal drugs and development of efficient antibacterial drugs.
authors.affiliation: Key Laboratory of Functional Protein Research of Guangdong Higher Education Institutes, Institute of Life and Health Engineering, College of Life Science and Technology, Jinan University, Guangzhou 510632, China; The First Affiliated Hospital of Jinan University,Guangzhou 510632, China.
authors.forename: Xiao-Yan
authors.initials: XY
authors.lastname: Yang
authors.affiliation: Key Laboratory of Functional Protein Research of Guangdong Higher Education Institutes, Institute of Life and Health Engineering, College of Life Science and Technology, Jinan University, Guangzhou 510632, China.
authors.forename: Liang
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Department of Chemistry, Jinan University, Guangzhou 510632, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Liu
authors.affiliation: Key Laboratory of Functional Protein Research of Guangdong Higher Education Institutes, Institute of Life and Health Engineering, College of Life Science and Technology, Jinan University, Guangzhou 510632, China.
authors.forename: Nan
authors.initials: N
authors.lastname: Li
authors.affiliation: Key Laboratory of Functional Protein Research of Guangdong Higher Education Institutes, Institute of Life and Health Engineering, College of Life Science and Technology, Jinan University, Guangzhou 510632, China.
authors.forename: Guangchuang
authors.initials: G
authors.lastname: Yu
authors.affiliation: Key Laboratory of Functional Protein Research of Guangdong Higher Education Institutes, Institute of Life and Health Engineering, College of Life Science and Technology, Jinan University, Guangzhou 510632, China.
authors.forename: Kun
authors.initials: K
authors.lastname: Cao
authors.affiliation: Key Laboratory of Functional Protein Research of Guangdong Higher Education Institutes, Institute of Life and Health Engineering, College of Life Science and Technology, Jinan University, Guangzhou 510632, China.
authors.forename: Junlong
authors.initials: J
authors.lastname: Han
authors.affiliation: Key Laboratory of Functional Protein Research of Guangdong Higher Education Institutes, Institute of Life and Health Engineering, College of Life Science and Technology, Jinan University, Guangzhou 510632, China.
authors.forename: Guandi
authors.initials: G
authors.lastname: Zeng
authors.affiliation: The First Affiliated Hospital of Jinan University,Guangzhou 510632, China.
authors.forename: Yunlong
authors.initials: Y
authors.lastname: Pan
authors.affiliation: Key Laboratory of Functional Protein Research of Guangdong Higher Education Institutes, Institute of Life and Health Engineering, College of Life Science and Technology, Jinan University, Guangzhou 510632, China. Electronic address: tsunxs@jnu.edu.cn.
authors.forename: Xuesong
authors.initials: X
authors.lastname: Sun
authors.affiliation: Key Laboratory of Functional Protein Research of Guangdong Higher Education Institutes, Institute of Life and Health Engineering, College of Life Science and Technology, Jinan University, Guangzhou 510632, China. Electronic address: tqyhe@jnu.edu.cn.
authors.forename: Qing-Yu
authors.initials: QY
authors.lastname: He
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000378:metabolism*; D002460:Cell Line; D006801:Humans; D040901:Proteomics; D012428:Ruthenium / Q000737:chemistry / Q000494:pharmacology*; D013296:Streptococcus pneumoniae / Q000378:metabolism*
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D012428:Ruthenium
keywords: Antibacterial activity; Proteomic profiling; Ru(II) complex; S. pneumoniae