Open conformation of a substrate-binding cleft: sup 19 F NMR studies of cleft angle in the D-galactose chemosensory receptor
- Univ. of Colorado, Boulder (United States)
The Escherichia coli D-galactose and D-glucose receptor is a two-domain structure with a sugar-binding site at the interface between domains. The structure of the closed cleft containing bound D-glucose has been determined crystalloghraphically, but the open cleft remains to be characterized. The present study illustrates a generalizable approach that is used to detect and analyze both the open- and closed-cleft conformations in solution. A {sup 19}F nucleus located inside the cleft is monitored by {sup 19}F NMR. When the cleft is occupied by D-glucose, the {sup 19}F nucleus is found to be inaccessible to the aqueous paramagnetic probe Gd{center dot}EDTA, verifying that the occupied cleft is closed in solution and inaccessible to bulk solvent. When the cleft is empty, the {sup 19}F nucleus becomes accessible to the paramagnet such that the distance of closest approach is r {le} 10 {angstrom}, indicating that the empty cleft opens at least transiently by an angle {theta} {ge} 18 {plus minus} 3{degrees}.
- OSTI ID:
- 5032373
- Journal Information:
- Biochemistry; (United States), Journal Name: Biochemistry; (United States) Vol. 30:26; ISSN 0006-2960; ISSN BICHA
- Country of Publication:
- United States
- Language:
- English
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59 BASIC BIOLOGICAL SCIENCES
ALDEHYDES
AMINO ACIDS
AROMATICS
AZAARENES
AZOLES
BACTERIA
CARBOHYDRATES
CARBOXYLIC ACIDS
CHELATING AGENTS
CONFORMATIONAL CHANGES
EDTA
ESCHERICHIA COLI
FLUORINATED ALIPHATIC HYDROCARBONS
FLUORINE 19
FLUORINE ISOTOPES
GALACTOSE
HALOGENATED ALIPHATIC HYDROCARBONS
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
HEXOSES
INDOLES
ISOTOPES
LIGHT NUCLEI
MAGNETIC RESONANCE
MEMBRANE PROTEINS
MICROORGANISMS
MONOSACCHARIDES
NUCLEAR MAGNETIC RESONANCE
NUCLEI
ODD-EVEN NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC FLUORINE COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PROTEINS
PYRROLES
RECEPTORS
RESONANCE
SACCHARIDES
STABLE ISOTOPES
SUBSTRATES
TRYPTOPHAN