Effects of pressure upon the fluorescence of the riboflavin binding protein and its flavin mononucleotide complex

Journal Article · Tue Jul 27 04:00:00 EDT 1976 · Biochemistry; (United States)

DOI:https://doi.org/10.1021/bi00660a008· OSTI ID:7156202

Li, T M; Hook, III, J W; Drickamer, H G; Weber, G

The effect of pressure in the range of 10/sup -3/-10 kbars upon the ultraviolet fluorescence of the riboflavin binding protein and the fluorescence of its complex with flavin mononucleotide has been studied. The fluorescence spectrum of the isolated protein showed a reversible red shift of 12 nm (1000 cm/sup -1/) at high pressure, indicating the reversible exposure of the tryptophan to solvent. From the pressure dependence of the visible fluorescence of the protein-flavin complex in the region of 1-4 kbars the volume change in dissociation of the protein-ligand complex was estimated to be +3.3 ml/mol. A very sharp increase in fluorescence--up to 30-fold of the low-pressure value--takes place in the region 5-8 kbars. This increase is due to release of the flavin from the complex and is assigned to pressure denaturation of the protein. The midpoint, p/sub /sup 1///sub 2//, of this transition was found at 6.5 kbars and the change in volume, ..delta..V, in the reaction (native-to-denatured) was calculated to be -74 ml/mol. Addition of up to 30 percent methanol results in a progressive decrease both in ..delta..V and p/sub /sup 1///sub 2//, in agreement with the concept that hydrophobic bonding stabilizes the native structure.

• Research Organization: Univ. of Illinois, Urbana
• OSTI ID: 7156202
• Journal Information: Biochemistry; (United States), Journal Name: Biochemistry; (United States) Vol. 15:15; ISSN BICHA
• Country of Publication: United States
• Language: English

Related Subjects

550200* -- Biochemistry
59 BASIC BIOLOGICAL SCIENCES
AMINO ACIDS
AZOLES
BIOCHEMISTRY
BONDING
CARBOXYLIC ACIDS
CHEMISTRY
FABRICATION
FLUORESCENCE
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
INDOLES
ISOALLOXAZINES
JOINING
LUMINESCENCE
NUCLEOTIDES
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
PRESSURE DEPENDENCE
PROTEINS
PYRROLES
RIBOFLAVIN
TRYPTOPHAN
VITAMIN B GROUP
VITAMINS