Although the importance of cation/proton antiporters in cellular physiology is well recognized and widely studied, many antiport systems remain underinvestigated. In this work, I report the phenotypic and biochemical effects of deletion of the cytoplasmic C-terminal tail of the NhaP2 antiporter from Vibrio cholerae (Vc-NhaP2). Namely, deletion of the C-terminal tail results in diminished K+/H+ and Na+/H+ antiport activity, as well as a 5-fold decrease in affinity for its major substrate, K+ (measured as the apparent Km at pH 7.5). Furthermore, reconstitution of antiport activity in the truncation mutant upon addition of exogenous C-terminal tail is demonstrated. Currently, the only known mechanism of antiport is for NhaA, which lacks a cytoplasmic tail. Therefore, these results suggest that NhaP2 may employ a novel mechanism of antiport in which the cytoplasmic tail is directly or indirectly involved.
| Identifer | oai:union.ndltd.org:MANITOBA/oai:mspace.lib.umanitoba.ca:1993/22193 |
| Date | 16 September 2013 |
| Creators | Wiens, Evan Jonathan |
| Contributors | Stetefeld, Joerg (Chemistry), Dibrov, Pavel (Microbiology) McKenna, Sean (Chemistry) Khajehpour, Mazdak (Chemistry) |
| Source Sets | University of Manitoba Canada |
| Detected Language | English |
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