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The Scientific World Journal
Volume 2012 (2012), Article ID 128705, 10 pages
http://dx.doi.org/10.1100/2012/128705
Research Article

Association of Acinetobacter baumannii EF-Tu with Cell Surface, Outer Membrane Vesicles, and Fibronectin

1Department of Biology, The University of Texas at San Antonio, One UTSA Circle, San Antonio, TX 78249, USA
2Department of Biomedical Engineering, The University of Texas at San Antonio, One UTSA Circle, San Antonio, TX 78249, USA
3Department of Biology, The University of Texas at Austin, 1 University Station, Austin, TX 78712, USA
4Pediatric Biochemistry Laboratory, The University of Texas at San Antonio, San Antonio, TX 78249, USA
5Department of Chemistry, The University of Texas at San Antonio, San Antonio, TX 78249, USA
6RCMI Proteomics and Protein Biomar Feers Cores, The University of Texas at San Antonio, San Antonio, TX 78249, USA
7Center for Research & Training in The Sciences, The University of Texas at San Antonio, San Antonio, TX 78249, USA
8Division of Hematology/Oncology, Department of Medicine, Cancer Therapy & Research Center, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
9Department of Biology, College of Science and Mathematics, Southwest Baptist University, 1600 University Avenue, Bolivar, MO 65613, USA

Received 22 November 2011; Accepted 24 January 2012

Academic Editors: G. Bruant, T. Darribere, S. F. Porcella, R. Rivas, and M. Vaneechoutte

Copyright © 2012 Shatha F. Dallo 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

A conundrum has long lingered over association of cytosol elongation factor Tu (EF-Tu) with bacterial surface. Here we investigated it with Acinetobacter baumannii, an emerging opportunistic pathogen associated with a wide spectrum of infectious diseases. The gene for A. baumannii EF-Tu was sequenced, and recombinant EF-Tu was purified for antibody development. EF-Tu on the bacterial surface and the outer membrane vesicles (OMVs) was revealed by immune electron microscopy, and its presence in the outer membrane (OM) and the OMV subproteomes was verified by Western blotting with the EF-Tu antibodies and confirmed by proteomic analyses. EF-Tu in the OM and the OMV subproteomes bound to fibronectin as detected by Western blot and confirmed by a label-free real-time optical sensor. The sensor that originates from photonic crystal structure in a total-Internal-reflection (PC-TIR) configuration was functionalized with fibronectin for characterizing EF-Tu binding. Altogether, with a novel combination of immunological, proteomical, and biophysical assays, these results suggest association of A. baumannii EF-Tu with the bacterial cell surface, OMVs, and fibronectin.