Table of Contents
International Journal of Proteomics
Volume 2016, Article ID 4029172, 9 pages
Research Article

Comparative Proteomic Analysis of Differential Proteins in Response to Aqueous Extract of Quercus infectoria Gall in Methicillin-Resistant Staphylococcus aureus

1School of Diagnostic & Applied Health Sciences, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz, 50300 Kuala Lumpur, Malaysia
2Department of Clinical Oral Biology, Faculty of Dentistry, Universiti Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz, 50300 Kuala Lumpur, Malaysia

Received 1 May 2016; Revised 27 July 2016; Accepted 3 August 2016

Academic Editor: Djuro Josic

Copyright © 2016 Radhiah Khairon 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.


The aim of this study is to analyze the differential proteins in MRSA ATCC 33591 treated with aqueous extract from Q. infectoria gall. Protein extracts were obtained from MRSA cells by sonication and were separated by 2D polyacrylamide gels. Protein spots of interest were extracted from the gels and identified using LC-ESI-QTOF MS. The concentration of Q. infectoria extract used for 2D-gel electrophoresis was subinhibitory concentration. Minimum inhibitory concentration (MIC) value of the extract against MRSA was 19.50 μg/mL with bacteriostatic action at 1x MIC from time-kill assay. However, the extract exhibited dose-dependent manner and was bactericidal at 4x MIC with more than 3 log10 CFU/mL reduction at 4 h. 2D-GE map showed that 18 protein spots were upregulated and another six were downregulated more than twofold () after treatment with subinhibitory concentration. Out of six proteins being downregulated, four proteins were identified as ferritin and catalase, branched-chain alpha-keto acid dehydrogenase subunit E2, and succinyl-CoA ligase [ADP-forming] subunit beta. Seven upregulated proteins which have been successfully identified were 3-hydroxyacyl-CoA dehydrogenase, NAD binding domain protein, formate C-acetyltransferase, 3-hydroxyacyl-[acyl-carrier-protein] dehydratase FabZ, NAD dependent epimerase/dehydratase family protein, and phosphopantothenoyl cysteine decarboxylase. It is postulated that the main mechanism of aqueous extract from gall of Q. infectoria was most likely involved in energy metabolism and protein stress.