کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1945678 1053271 2007 9 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
The Enterobacter aerogenes outer membrane efflux proteins TolC and EefC have different channel properties
موضوعات مرتبط
علوم زیستی و بیوفناوری بیوشیمی، ژنتیک و زیست شناسی مولکولی زیست شیمی
پیش نمایش صفحه اول مقاله
The Enterobacter aerogenes outer membrane efflux proteins TolC and EefC have different channel properties
چکیده انگلیسی

The outer membrane proteins TolC and EefC from Enterobacter aerogenes are involved in multidrug resistance as part of two resistance-nodulation-division efflux systems. To gain more understanding in the molecular mechanism underlying drug efflux, we have undertaken an electrophysiological characterization of the channel properties of these two proteins. TolC and EefC were purified in their native trimeric form and then reconstituted in proteoliposomes for patch-clamp experiments and in planar lipid bilayers. Both proteins generated a small single channel conductance of about 80 pS in 0.5 M KCl, indicating a common gated structure. The resultant pores were stable, and no voltage-dependent openings or closures were observed. EefC has a low ionic selectivity (PK/PCl = ∼ 3), whereas TolC is more selective to cations (PK/PCl = ∼ 30). This may provide a possible explanation for the difference in drug selectivity between the AcrAB-TolC and EefABC efflux systems observed in vivo. The pore-forming activity of both TolC and EefC was severely inhibited by divalent cations entering from the extracellular side. Another characteristic of the TolC and EefC channels was the systematic closure induced by acidic pH. These results are discussed in respect to the physiological functions and structural models of TolC and EefC.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Biochimica et Biophysica Acta (BBA) - Biomembranes - Volume 1768, Issue 10, October 2007, Pages 2559–2567
نویسندگان
, , , ,