کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1960083 1057950 2005 10 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
A Salt-Bridge Motif Involved in Ligand Binding and Large-Scale Domain Motions of the Maltose-Binding Protein
موضوعات مرتبط
علوم زیستی و بیوفناوری بیوشیمی، ژنتیک و زیست شناسی مولکولی زیست شیمی
پیش نمایش صفحه اول مقاله
A Salt-Bridge Motif Involved in Ligand Binding and Large-Scale Domain Motions of the Maltose-Binding Protein
چکیده انگلیسی

The uptake of nutrients is essential for the survival of bacterial cells. Many specialized systems have evolved, such as the maltose-dependent ABC transport system that transfers oligosaccharides through the cytoplasmic membrane. The maltose/maltodextrin-binding protein (MBP) serves as an initial high-affinity binding component in the periplasm that delivers the bound sugar into the cognate ABC transporter MalFGK2. We have investigated the domain motions induced by the binding of the ligand maltotriose into the binding cleft using molecular dynamics simulations. We find that MBP is predominantly in the open state without ligand and in the closed state with ligand bound. Oligosaccharide binding induces a closure motion (30.0° rotation), whereas ligand removal leads to domain opening (32.6° rotation) around a well-defined hinge affecting key areas relevant for chemotaxis and transport. Our simulations suggest that a “hook-and-eye” motif is involved in the binding. A salt bridge between Glu-111 and Lys-15 forms that effectively locks the protein-ligand complex in a semiclosed conformation inhibiting any further opening and promoting complete closure. This previously unrecognized feature seems to secure the ligand in the binding site and keeps MBP in the closed conformation and suggests a role in the initial steps of substrate transport.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: - Volume 89, Issue 5, November 2005, Pages 3362–3371
نویسندگان
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