Open conformation of a substrate-binding cleft: sup 19 F NMR studies of cleft angle in the D-galactose chemosensory receptor

Journal Article · Tue Jul 02 00:00:00 EDT 1991 · Biochemistry; (United States)

DOI:https://doi.org/10.1021/bi00240a019· OSTI ID:5032373

Luck, L A; Falke, J J ^[1]

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1. 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), Vol. 30:26; ISSN 0006-2960
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
RECEPTORS
NUCLEAR MAGNETIC RESONANCE
SUBSTRATES
CONFORMATIONAL CHANGES
EDTA
ESCHERICHIA COLI
FLUORINATED ALIPHATIC HYDROCARBONS
FLUORINE 19
GALACTOSE
TRYPTOPHAN
ALDEHYDES
AMINO ACIDS
AROMATICS
AZAARENES
AZOLES
BACTERIA
CARBOHYDRATES
CARBOXYLIC ACIDS
CHELATING AGENTS
FLUORINE ISOTOPES
HALOGENATED ALIPHATIC HYDROCARBONS
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
HEXOSES
INDOLES
ISOTOPES
LIGHT NUCLEI
MAGNETIC RESONANCE
MEMBRANE PROTEINS
MICROORGANISMS
MONOSACCHARIDES
NUCLEI
ODD-EVEN NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC FLUORINE COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PROTEINS
PYRROLES
RESONANCE
SACCHARIDES
STABLE ISOTOPES
550201* - Biochemistry- Tracer Techniques