کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1937153 1050710 2007 6 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Characterization of the multidrug efflux regulator AcrR from Escherichia coli
موضوعات مرتبط
علوم زیستی و بیوفناوری بیوشیمی، ژنتیک و زیست شناسی مولکولی زیست شیمی
پیش نمایش صفحه اول مقاله
Characterization of the multidrug efflux regulator AcrR from Escherichia coli
چکیده انگلیسی

The Escherichia coli AcrR represses transcription of the acrB gene, which encodes the multidrug efflux pump AcrB that extrudes a wide variety of toxic compounds, by binding its target operator DNA. Fluorescence polarization was performed using purified, recombinant AcrR that contains a 6xHis tag at the C-terminus and a fluorescein-labeled 28-base pair oligonucleotide bearing a predicted palindrome (IR) operator sequence. Binding of AcrR to the predicted IR sequence occurred with a dissociation constant (KD) in the nanomolar range. Fluorescence polarization assays were also applied to characterize the affinity and specificity of AcrR interaction with three different fluorescent ligands, rhodamine 6G, ethidium, and proflavin. The KD values for these ligands range from 4.2 to 10.1 μM, suggesting that AcrR is capable of recognizing a wide range of structurally dissimilar toxic compounds as it is in the case of the AcrB multidrug efflux pump. We found that the binding of rhodamine 6G to AcrR is inhibited by the presence of ethidium. In contrast, the dissociation constant of proflavin binding to AcrR was not affected by ethidium, a result suggesting that ethidium and proflavin are bound to distinct binding sites.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Biochemical and Biophysical Research Communications - Volume 361, Issue 1, 14 September 2007, Pages 85–90
نویسندگان
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