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BioMed Research International
Volume 2017, Article ID 3076091, 8 pages
https://doi.org/10.1155/2017/3076091
Research Article

Purification and Characterization of an ATPase GsiA from Salmonella enterica

1Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, China
2Department of Gynecology, Central Hospital of Xuzhou, Affiliated Hospital of Southeast University, Xuzhou, China
3Department of Microbiology, College of Resource and Environmental Sciences, Sichuan Agricultural University, Chengdu, China

Correspondence should be addressed to Zhongshan Wang; moc.621@258szw and Meng Zhang; moc.621@701068gnemia

Received 16 December 2016; Revised 23 March 2017; Accepted 13 April 2017; Published 12 June 2017

Academic Editor: Ernesto S. Nakayasu

Copyright © 2017 Zhongshan Wang et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The coding sequence of Salmonella enterica gsiA was cloned and expressed in E. coli. The protein was purified and ATPase activity was characterized by NADH oxidation method. GsiA exhibited optimum activity at 30°C and at pH 8 in Tris/HCl buffer. GsiA protein was stable at 20°C. 66% and 44% activity remained after incubation at 30°C and 40°C for 30 min. pH 7 and pH 9 incubation would obviously reduce the ATPase activity. In vivo functionality of gsiA was determined by constructing gene deletion strains. gsiA was shown to be essential for GSI mediated glutathione uptake and gsiA deletion could decrease the virulence of Salmonella enterica. Interactions of glutathione import proteins GsiA, GsiB, GsiC, and GsiD were investigated by using bacterial two-hybrid system. GsiA could interact with itself and inner membrane proteins GsiC and GsiD. This report provides the first description of gsiA functions in Salmonella enterica. The results could help elucidating the glutathione uptake mechanism and glutathione functions in bacteria.