Flinders Academic Commons >
Research Publications >
ERA 2010 >
06 - Biological Sciences and Biotechnology >
0605 - Microbiology >
Please use this identifier to cite or link to this item:
|Title: ||Functional analyses reveal an important role for
tyrosine residues in the staphylococcal multidrug efflux protein QacA|
|Authors: ||Brown, Melissa Hackett|
Hassan, Karl Adam
Skurray, Ronald Anthony
|Issue Date: ||2008|
|Citation: ||Wu, J., Hassan, K.A., Skurray, R.A.,
& Brown, M.H., 2008. Functional analyses reveal an important role for tyrosine
residues in the staphylococcal multidrug efflux protein QacA. BMC Microbiology,
The staphylococcal QacA multidrug efflux protein confers resistance to an exceptional number of structurally unrelated antimicrobial compounds. Aromatic amino acid residues have been shown to be highly important for the transport function of several multidrug transporters and are intimately involved in multidrug binding. This study investigated the structural and functional importance of the seven tyrosine residues in QacA by examining the phenotypic effect of incorporating conservative (aromatic) and non-conservative (non-aromatic) substitutions for these residues.
Determination of the resistance profiles and analysis of drug transport assays revealed that non-conservative substitutions for most tyrosine residues influenced the QacA drug recognition spectrum. However, an aromatic residue at three tyrosine positions, 63, 410 and 429, was of importance for QacA-mediated transport and resistance to the majority of substrates tested.
A tyrosine or phenylalanine residue at amino acid positions corresponding to 63 of QacA in related drug efflux proteins is found to be highly conserved. Therefore, an aromatic side chain at this position is likely to partake in a function common to these drug transporters, such as proton translocation or essential intramolecular contacts, whereas aromatic residues at the non-conserved 410 and 429 positions are expected to mediate a QacA-specific function, possibly forming or stabilising part of the QacA drug binding region.|
|Description: ||© 2008 Wu et al; licensee BioMed Central Ltd.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.|
|Appears in Collections:||0605 - Microbiology|
0605 - Microbiology
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.