کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
2187545 1096125 2008 8 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Kinetics and Energetics of the Translocation of Maltose Binding Protein Folding Mutants
موضوعات مرتبط
علوم زیستی و بیوفناوری بیوشیمی، ژنتیک و زیست شناسی مولکولی بیولوژی سلول
پیش نمایش صفحه اول مقاله
Kinetics and Energetics of the Translocation of Maltose Binding Protein Folding Mutants
چکیده انگلیسی

Protein translocation in Escherichia coli is mediated by the translocase that, in its minimal form, comprises a protein-conducting pore (SecYEG) and a motor protein (SecA). The SecYEG complex forms a narrow channel in the membrane that allows passage of secretory proteins (preproteins) in an unfolded state only. It has been suggested that the SecA requirement for translocation depends on the folding stability of the mature preprotein domain. Here we studied the effects of the signal sequence and SecB on the folding and translocation of folding stabilizing and destabilizing mutants of the mature maltose binding protein (MBP). Although the mutations affect the folding of the precursor form of MBP, these are drastically overruled by the combined unfolding stabilization of the signal sequence and SecB. Consequently, the translocation kinetics, the energetics and the SecA and SecB dependence of the folding mutants are indistinguishable from those of wild-type preMBP. These data indicate that unfolding of the mature domain of preMBP is likely not a rate-determining step in translocation when the protein is targeted to the translocase via SecB.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Molecular Biology - Volume 377, Issue 1, 14 March 2008, Pages 83–90
نویسندگان
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