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Conformational changes of glucose/galactose-binding protein illuminated by open, unliganded, and ultra-high-resolution ligand-bound structures.

ABSTRACT: D-Glucose/D-Galactose-binding protein (GGBP) mediates chemotaxis toward and active transport of glucose and galactose in a number of bacterial species. GGBP, like other periplasmic binding proteins, can exist in open (ligand-free) and closed (ligand-bound) states. We report a 0.92 angstroms resolution structure of GGBP from Escherichia coli in the glucose-bound state and the first structure of an open, unbound form of GGBP (at 1.55 angstroms resolution). These structures vary in the angle between the two structural domains; the observed difference of 31 degrees arises from torsion angle changes in a three-segment hinge. A comparison with the closely related periplasmic receptors, ribose- and allose-binding proteins, shows that the GGBP hinge residue positions that undergo the largest conformational changes are different. Furthermore, the high-quality data collected for the atomic resolution glucose-bound structure allow for the refinement of specific hydrogen atom positions, the assignment of alternate side chain conformations, the first description of CO(2) trapped after radiation-induced decarboxylation, and insight into the role of the exo-anomeric effect in sugar binding. Together, these structures provide insight into how the hinge-bending movement of GGBP facilitates ligand binding, transport, and signaling.

SUBMITTER: Borrok MJ

PROVIDER: S-EPMC2206672 | biostudies-literature | 2007 Jun

REPOSITORIES: biostudies-literature

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Conformational changes of glucose/galactose-binding protein illuminated by open, unliganded, and ultra-high-resolution ligand-bound structures.

Borrok M Jack MJ Kiessling Laura L LL Forest Katrina T KT

Protein science : a publication of the Protein Society 20070501 6

D-Glucose/D-Galactose-binding protein (GGBP) mediates chemotaxis toward and active transport of glucose and galactose in a number of bacterial species. GGBP, like other periplasmic binding proteins, can exist in open (ligand-free) and closed (ligand-bound) states. We report a 0.92 angstroms resolution structure of GGBP from Escherichia coli in the glucose-bound state and the first structure of an open, unbound form of GGBP (at 1.55 angstroms resolution). These structures vary in the angle betwee ...[more]

PMID: 17473016

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Dataset Information

Conformational changes of glucose/galactose-binding protein illuminated by open, unliganded, and ultra-high-resolution ligand-bound structures.

Publications

Conformational changes of glucose/galactose-binding protein illuminated by open, unliganded, and ultra-high-resolution ligand-bound structures.

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