کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1959153 1057928 2006 10 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Chemical Modification of the Bacterial Porin OmpF: Gain of Selectivity by Volume Reduction
موضوعات مرتبط
علوم زیستی و بیوفناوری بیوشیمی، ژنتیک و زیست شناسی مولکولی زیست شیمی
پیش نمایش صفحه اول مقاله
Chemical Modification of the Bacterial Porin OmpF: Gain of Selectivity by Volume Reduction
چکیده انگلیسی

OmpF is an essentially nonselective porin isolated from the outer membrane of Escherichia coli. Here we report on the manipulation of the ion selectivity of OmpF by chemical modification with MTS reagents (MTSET, MTSEA, and MTSES) and the (rather bulky) tripeptide glutathione, all cysteine specific. When recorded in a gradient of 0.1//1 M CaCl2 or 0.1//1 M NaCl, pH 7.4 solutions, measured reversal potentials of the most cation-selective modified mutants were (virtually) identical to the Nernst potential of Ca2+ or Na+. Compared to this full cation selectivity, the anion-selective modified mutants performed somewhat less but nevertheless showed high anion selectivity. We conclude that a low permanent charge in combination with a narrow pore can render the same selectivity as a highly charged but wider pore. These results favor the view that both the electrostatic potential arising form the fixed charge in the pore and the space available at the selectivity filter contribute to the charge selection (i.e., cation versus anion selectivity) of a biological ion channel.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: - Volume 90, Issue 4, 15 February 2006, Pages 1202–1211
نویسندگان
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