A PRO TO GLY MUTATION IN THE HINGE OF THE ARABINOSE-BINDING PROTEIN ENHANCES BINDING AND ALTERS SPECIFICITY: SUGAR-BINDING AND CRYSTALLOGRAPHIC STUDIES
A Pro to Gly mutation in the hinge of the arabinose-binding protein enhances binding and alters specificity. Sugar-binding and crystallographic studies.
Primary Citation of Related Structures: 1APB, 1BAP, 9ABP
PubMed Abstract:
The L-arabinose-binding protein (ABP) of Escherichia coli consists structurally of two distinct globular domains connected by a hinge of three separate peptide segments. Arabinose is bound and completely sequestered within the deep cleft between the two domains ...
The L-arabinose-binding protein (ABP) of Escherichia coli consists structurally of two distinct globular domains connected by a hinge of three separate peptide segments. Arabinose is bound and completely sequestered within the deep cleft between the two domains. With reduced affinity, ABP also binds D-galactose (approximately 2-fold reduction) and D-fucose (approximately 40-fold reduction). Experiments have been conducted to explore the role in sugar binding of the hinge connecting the two domains of ABP. To increase the flexibility of the hinge region, a glycine was substituted for a proline at position 254 by site-directed mutagenesis. Unexpectedly, this mutation resulted in the dramatic enhancement of galactose binding over that of arabinose. The affinity of the mutant ABP for galactose increased by over 20-fold, while that for arabinose and fucose remained relatively unchanged. We have measured association and dissociation rates of the Gly-254 ABP with L-arabinose, D-galactose, and D-fucose and have determined the crystallographic structure of the protein complexed with each of the three sugars. Both the ligand-binding kinetic measurements and structure analysis indicate that the altered specificity is due to an effective increase in the rigidity of the hinge in the closed conformation which is induced upon galactose binding. Stabilizing contacts are formed between the strands of the hinge in the Gly-254 ABP when galactose is bound which are not found in complexes with the other sugars or the liganded wild-type protein.
Related Citations:
Substrate Specificity and Affinity of a Protein Modulated by Bound Water Molecules Quiocho, F.A., Wilson, D.K., Vyas, N.K. (1989) Nature 340: 404
Novel Stereospecificity of the L-Arabinose-Binding Protein Quiocho, F.A., Vyas, N.K. (1984) Nature 310: 381
Hinge-Bending in L-Arabinose-Binding Protein. The "Venus'S-Flytrap" Model Mao, B., Pear, M.R., Mccammon, J.A., Quiocho, F.A. (1982) J Biol Chem 257: 1131
Structure of the L-Arabinose-Binding Protein from Escherichia Coli at 2.4 Angstroms Resolution Gilliland, G.L., Quiocho, F.A. (1981) J Mol Biol 146: 341
L-Arabinose-Binding Protein-Sugar Complex at 2.4 Angstroms Resolution. Stereochemistry and Evidence for a Structural Change Newcomer, M.E., Gilliand, G.L., Quiocho, F.A. (1981) J Biol Chem 256: 13213
The Radius of Gyration of L-Arabinose-Binding Protein Decreases Upon Binding of Ligand Newcomer, M.E., Lewis, B.A., Quiocho, F.A. (1981) J Biol Chem 256: 13218
The Thiol Group of the L-Arabinose-Binding Protein. Chromophoric Labeling and Chemical Identification of the Sugar-Binding Site Miller /III, D.M., Newcomer, M.E., Quiocho, F.A. (1979) J Biol Chem 254: 7521
Location of the Sugar-Binding Site of L-Arabinose-Binding Protein. Sugar Derivative Syntheses, Sugar Binding Specificity, and Difference Fourier Analyses Newcomer, M.E., Miller /III, D.M., Quiocho, F.A. (1979) J Biol Chem 254: 7529
The 2.8-Angstroms Resolution Structure of the L-Arabinose-Binding Protein from Escherichia Coli Quiocho, F.A., Gilliland, G.L., Phillips Jr., G.N. (1977) J Biol Chem 252: 5142
Structure of L-Arabinose-Binding Protein from Escherichia Coli at 5 Angstroms Resolution and Preliminary Results at 3.5 Angstroms Phillips Jr., G.N., Mahajan, V.K., Siu, A.K.Q., Quiocho, F.A. (1976) Proc Natl Acad Sci U S A 73: 2186
Organizational Affiliation:
Howard Hughes Medical Institute, Baylor College of Medicine, Houston, Texas 77030.
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