Identification of NuoX and NuoY Ligand Binding Specificity in the Campylobacter Jejuni Complex ILirio I. Calderon-Gomez1, Christopher J. Day1, Lauren E. Hartley-Tassell1, Jennifer C. Wilson1, George L. Mendz2 and Victoria Korolik1*
- *Corresponding Author:
- Professor Victoria Korolik
Institute for Glycomics, Griffith University
Gold Coast, Queensland, 4222, Australia
E-mail: [email protected]
Received Date: April 05, 2017; Accepted Date: April 21, 2017; Published Date: April 26, 2017
Citation: Calderon-Gomez LI, Day CJ, Hartley-Tassell LE, Wilson JC, Mendz GL, et al. (2017) Identification of nuoX and NuoY Ligand Binding Specificity in the Campylobacter Jejuni Complex I. J Bacteriol Parasitol 8:307. doi: 10.4172/2155-9597.1000307
Copyright: © 2017 Calderon-Gomez LI, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
The components of the proton pump NADH:ubiquinone (Complex I) of the respiration pathway have been identified in the C. jejuni genome. However, the paradigm genes nuoE and nuoF encoding subunits of the NADH dehydrogenase module of Complex I are absent. Instead the genes cj1575c and cj1574c encoding NuoX and NuoY are present in the loci corresponding to nuoE and nuoF, respectively. Bioinformatics analyses showed the presence of nuoX and nuoY homologues in all sequenced strains of C. jejuni and in other Campylobacter species, as well as the presence of orthologues in other ÃÂ-Proteobacteria. To understand the involvement of the NuoX and NuoY proteins in the respiration of C. jejuni and to characterize their ligand binding specificity and affinity, a tricarboxylic acid cycle array was developed as a tool to identify proteins that can bind to intermediates of this cycle as well as other metabolites. This array showed that NuoX bound FAD2+, and NuoY bound FAD2+ and the electron donors malate and lactate. Saturation Transfer Difference Nuclear Magnetic Resonance studies confirmed the NuoY binding ligands, and suggested that the flavin moiety of FAD2+ interacted more strongly with NuoY than the adenine moiety. Affinity data generated by Surface Plasmon Resonance indicated that NuoY bound to FAD2+ with a KD of 337 nM; NuoX and NuoY had an affinity for NADH of a KD of 403 nM and 478 nM, respectively, and a ten-fold lower affinity for both NAD+ and FAD2+. The data suggested that the flavin-adenine dinucletoide could be bound preferentially to the NAD in the Complex I of C. jejuni.