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Visualization of ATP Synthase Dimers in Mitochondria by Electron Cryo-tomography
Published on: September 14, 2014
Crystal structure of riboflavin synthase
D I Liao1, Z Wawrzak, J C Calabrese
1DuPont Central Research and Development, Experimental Station, 19880, Wilmington, DE, USA. der-ing.liao@usa.dupont.com
Structure (London, England : 1993)
|May 30, 2001
Summary
Riboflavin synthase, a target for antimicrobials, was structurally characterized. Its trimeric form suggests only one active site is catalytically competent at a time.
Area of Science:
- Biochemistry
- Structural Biology
- Enzymology
Background:
- Riboflavin synthase is crucial for riboflavin biosynthesis in many organisms.
- The enzyme is a homotrimer and a potential antimicrobial target as it's absent in humans.
- It catalyzes the conversion of 6,7-dimethyl-8-(1'-D-ribityl)-lumazine to riboflavin.
Purpose of the Study:
- To determine the three-dimensional structure of riboflavin synthase.
- To elucidate the structural basis for its catalytic mechanism.
- To provide insights for antimicrobial drug development.
Main Methods:
- X-ray crystallography at 2.0 A resolution.
- Multiwavelength anomalous diffraction (MAD) method.
- Use of Escherichia coli protein with selenomethionine residues.
Main Results:
- The first 3D structure of riboflavin synthase was determined.
- The homotrimer comprises monomers with two similar beta barrels and a C-terminal alpha helix.
- Beta barrel folds resemble those in phthalate dioxygenase reductase and other flavoproteins.
Conclusions:
- Proposed active sites are located between monomer pairs, containing conserved residues like Asp-His-Ser triads.
- FMN modeling suggests active sites are positioned similarly to phthalate dioxygenase reductase.
- The trimeric structure indicates only one active site is catalytically functional at any given time.
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