کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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2186654 | 1096070 | 2009 | 9 صفحه PDF | دانلود رایگان |
Urea transporters (UTs) facilitate urea permeation across cell membranes in prokaryotes and eukaryotes. Bacteria use urea as a means to survive in acidic environments and/or as a nitrogen source. The UT from Actinobacillus pleuropneumoniae, ApUT, the pathogen that causes porcine pleurisy and pneumonia, was expressed in Escherichia coli and purified. Analysis of the recombinant protein using cross-linking and blue-native gel electrophoresis established that ApUT is a dimer in detergent solution. Purified protein was reconstituted into proteoliposomes and urea efflux was measured by stopped-flow fluorometry to determine the urea transport kinetics of ApUT. The measured urea flux was saturable, could be inhibited by phloretin, and was not affected by pH. Two-dimensional crystals of the biologically active ApUT show that it is also dimeric in a lipid membrane and provide the first structural information on a member of the UT family.
Journal: Journal of Molecular Biology - Volume 387, Issue 3, 3 April 2009, Pages 619–627