title: Conformational analysis of the GTP-binding protein MxA using limited proteolysis.
abstract: Guanosine triphosphate (GTP)-binding proteins are known to function as molecular switches that cycle between GTP-bound and guanosine diphosphate (GDP)-bound states. Switching is achieved by the fact that G-proteins in the GTP-bound conformation can interact with a certain set of effector molecules while they interact with a different set of partners in their GDP-bound conformation. The antiviral properties of the interferon-induced MxA protein are critically dependent on the ability of MxA to bind GTP. Using limited proteolysis we analyzed the conformations of the MxA protein under nucleotide-free, GDP-bound, and GTP-bound conditions. We find that whereas the conformations of nucleotide-free MxA and GDP-bound MxA are essentially similar, GTP-binding causes a dramatic change in the conformation of MxA.
authors.affiliation: Tata Institute of Fundamental Research, Bombay, India.
authors.forename: Anjali
authors.initials: A
authors.lastname: Varne
authors.forename: Karthika
authors.initials: K
authors.lastname: Muthukumaraswamy
authors.forename: Shashidhar S
authors.initials: SS
authors.lastname: Jatiani
authors.forename: Rohit
authors.initials: R
authors.lastname: Mittal
mesh_terms: D000818:Animals; D000998:Antiviral Agents / Q000737:chemistry / Q000378:metabolism; D019286:Endopeptidase K; D019204:GTP-Binding Proteins / Q000737:chemistry* / Q000378:metabolism; D006153:Guanosine Diphosphate / Q000378:metabolism; D006160:Guanosine Triphosphate / Q000378:metabolism; D066298:In Vitro Techniques; D064547:Myxovirus Resistance Proteins; D010206:Papain; D011485:Protein Binding; D011487:Protein Conformation; D011506:Proteins / Q000737:chemistry* / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D014357:Trypsin
chemical_list: D000998:Antiviral Agents; D064547:Myxovirus Resistance Proteins; D011506:Proteins; D011994:Recombinant Proteins; D006153:Guanosine Diphosphate; D006160:Guanosine Triphosphate; D014357:Trypsin; D019286:Endopeptidase K; D010206:Papain; D019204:GTP-Binding Proteins