title: Ligand binding properties of the N-terminal domain of riboflavin synthase from Escherichia coli.
abstract: Riboflavin synthase from Escherichia coli is a homotrimer of 23.4 kDa subunits and catalyzes the formation of one molecule each of riboflavin and 5-amino-6-ribitylamino- 2,4(1H,3H)-pyrimidinedione by the transfer of a 4-carbon moiety between two molecules of the substrate, 6,7- dimethyl-8-ribityllumazine. Each subunit comprises two closely similar folding domains. Recombinant expression of the N-terminal domain is known to provide a c(2)-symmetric homodimer. In this study, the binding properties of wild type as well as two mutated proteins of N-terminal domain of riboflavin synthase with various ligands were tested. The replacement of the amino acid residue A43, located in the second shell of riboflavin synthase active center, in the recombinant N-terminal domain dimer reduces the affinity for 6,7-dimethyl-8-ribityllumazine. The mutation of the amino acid residue C48 forming part of activity cavity of the enzyme causes significant (19)F NMR chemical shift modulation of trifluoromethyl derivatives of 6,7-dimethyl-8-ribityllumazine in complex with the protein, while substitution of A43 results in smaller chemical shift changes.
authors: Lehrstuhl fur Organische Chemie und Biochemie, Technische Universitat Munchen, D-85747 Garching, Germany. adelbert.bacher@ch.tum.de
authors: Chan Yong
authors: CY
authors: Lee
authors: Boris
authors: B
authors: Illarionov
authors: Young-Eun
authors: YE
authors: Woo
authors: Kristina
authors: K
authors: Kemter
authors: Ryu-Ryun
authors: RR
authors: Kim
authors: Sabine
authors: S
authors: Eberhardt
authors: Mark
authors: M
authors: Cushman
authors: Wolfgang
authors: W
authors: Eisenreich
authors: Markus
authors: M
authors: Fischer
authors: Adelbert
authors: A
authors: Bacher
mesh_terms: D000595:Amino Acid Sequence; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000201:enzymology*; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008969:Molecular Sequence Data; D050505:Mutant Proteins / Q000737:chemistry / Q000378:metabolism; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D012258:Riboflavin Synthase / Q000737:chemistry* / Q000378:metabolism*; D013237:Stereoisomerism; D013379:Substrate Specificity; D017186:Titrimetry
chemical_list: D008024:Ligands; D050505:Mutant Proteins; D012258:Riboflavin Synthase