title: Crystal structures of the ATPase subunit of the glucose ABC transporter from Sulfolobus solfataricus: nucleotide-free and nucleotide-bound conformations.
abstract: The ABC-ATPase GlcV energizes a binding protein-dependent ABC transporter that mediates glucose uptake in Sulfolobus solfataricus. Here, we report high-resolution crystal structures of GlcV in different states along its catalytic cycle: distinct monomeric nucleotide-free states and monomeric complexes with ADP-Mg(2+) as a product-bound state, and with AMPPNP-Mg(2+) as an ATP-like bound state. The structure of GlcV consists of a typical ABC-ATPase domain, comprising two subdomains, connected by a linker region to a C-terminal domain of unknown function. Comparisons of the nucleotide-free and nucleotide-bound structures of GlcV reveal re-orientations of the ABCalpha subdomain and the C-terminal domain relative to the ABCalpha/beta subdomain, and switch-like rearrangements in the P-loop and Q-loop regions. Additionally, large conformational differences are observed between the GlcV structures and those of other ABC-ATPases, further emphasizing the inherent flexibility of these proteins. Notably, a comparison of the monomeric AMPPNP-Mg(2+)-bound GlcV structure with that of the dimeric ATP-Na(+)-bound LolD-E171Q mutant reveals a +/-20 degrees rigid body re-orientation of the ABCalpha subdomain relative to the ABCalpha/beta subdomain, accompanied by a local conformational difference in the Q-loop. We propose that these differences represent conformational changes that may have a role in the mechanism of energy-transduction and/or allosteric control of the ABC-ATPase activity in bacterial importers.
authors.affiliation: Laboratory of Biophysical Chemistry, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands.
authors.forename: Grégory
authors.initials: G
authors.lastname: Verdon
authors.forename: Sonja V
authors.initials: SV
authors.lastname: Albers
authors.forename: Bauke W
authors.initials: BW
authors.lastname: Dijkstra
authors.forename: Arnold J M
authors.initials: AJ
authors.lastname: Driessen
authors.forename: Andy Mark W H
authors.initials: AM
authors.lastname: Thunnissen
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000737:chemistry* / Q000235:genetics; D000227:Adenine Nucleotides / Q000378:metabolism; D000251:Adenosine Triphosphatases / Q000737:chemistry* / Q000235:genetics; D000255:Adenosine Triphosphate / Q000378:metabolism; D000595:Amino Acid Sequence; D001665:Binding Sites; D018360:Crystallography, X-Ray; D008274:Magnesium / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011487:Protein Conformation; D021122:Protein Subunits; D017386:Sequence Homology, Amino Acid; D055672:Static Electricity; D016944:Sulfolobus / Q000201:enzymology* / Q000235:genetics
chemical_list: D018528:ATP-Binding Cassette Transporters; D000227:Adenine Nucleotides; D021122:Protein Subunits; D000255:Adenosine Triphosphate; D000251:Adenosine Triphosphatases; D008274:Magnesium