کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
637118 1456147 2009 6 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Directional ion selectivity in a biological nanopore with bipolar structure
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی تصفیه و جداسازی
پیش نمایش صفحه اول مقاله
Directional ion selectivity in a biological nanopore with bipolar structure
چکیده انگلیسی

Ion transport features of a biological nanopore, the bacterial porin OmpF from Escherichia coli, have been investigated by patch-clamp experiments performed at the single channel level. Membrane potential measurements done under asymmetric conditions of pH and electrolyte concentration provide important evidences about the charge regulation exerted by the channel that cannot be extracted from the rectification displayed in current–voltage curves. The pH gradient imposed across the pore induces an asymmetric fixed-charge distribution that resembles the structure of synthetic bipolar membranes. This particular arrangement demonstrates that the ionic selectivity of a non-uniformly charged structure is not an intrinsic quality of the system but depends crucially on several external factors. Amazingly, changing the direction of the salt concentration gradient can turn a cation selective channel into an anion selective one.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Membrane Science - Volume 331, Issues 1–2, 1 April 2009, Pages 137–142
نویسندگان
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