Structure of {alpha}-Glycerophosphate Oxidase from Streptococcus sp.: A Template for the Mitochondrial {alpha}-Glycerophosphate Dehydrogenase

Journal Article · Tue Jan 01 04:00:00 EST 2008 · Biochemistry

DOI:https://doi.org/10.1021/bi701685u· OSTI ID:959819

Colussi, T; Parsonage, D; Boles, W; Matsuoka, T; Mallett, T; Karplus, P; Clairborne, A

The FAD-dependent a-glycerophosphate oxidase (GlpO) from Enterococcus casseliflavus and Streptococcus sp. was originally studied as a soluble flavoprotein oxidase; surprisingly, the GlpO sequence is 30-43% identical to those of the a-glycerophosphate dehydrogenases (GlpDs) from mitochondrial and bacterial sources. The structure of a deletion mutant of Streptococcus sp. GlpO (GlpO?, lacking a 50-residue insert that includes a flexible surface region) has been determined using multiwavelength anomalous dispersion data and refined at 2.3 Angstroms resolution. Using the GlpO? structure as a search model, we have also determined the intact GlpO structure, as refined at 2.4 Angstroms resolution. The first two domains of the GlpO fold are most closely related to those of the flavoprotein glycine oxidase, where they function in FAD binding and substrate binding, respectively; the GlpO C-terminal domain consists of two helix bundles and is not closely related to any known structure. The flexible surface region in intact GlpO corresponds to a segment of missing electron density that links the substrate-binding domain to a {beta}a element of the FAD-binding domain. In accordance with earlier biochemical studies (stabilizations of the covalent FAD-N5-sulfite adduct and p-quinonoid form of 8-mercapto-FAD), Ile430-N, Thr431-N, and Thr431-OG are hydrogen bonded to FAD-O2a in GlpO?, stabilizing the negative charge in these two modified flavins and facilitating transfer of a hydride to FAD-N5 (from Glp) as well. Active-site overlays with the glycine oxidase-N-acetylglycine and d-amino acid oxidase-d-alanine complexes demonstrate that Arg346 of GlpO? is structurally equivalent to Arg302 and Arg285, respectively; in both cases, these residues interact directly with the amino acid substrate or inhibitor carboxylate. The structural and functional divergence between GlpO and the bacterial and mitochondrial GlpDs is also discussed.

• Research Organization: Brookhaven National Laboratory (BNL) National Synchrotron Light Source
• Sponsoring Organization: Doe - Office Of Science
• DOE Contract Number: AC02-98CH10886
• OSTI ID: 959819
• Report Number(s): BNL--82805-2009-JA
• Journal Information: Biochemistry, Journal Name: Biochemistry Vol. 47; ISSN 0006-2960; ISSN BICHAW
• Country of Publication: United States
• Language: English

Related Subjects

08 HYDROGEN
ADDUCTS
AMINO ACIDS
ELECTRON DENSITY
FUNCTIONALS
GLYCINE
HYDRIDES
HYDROGEN
ISOALLOXAZINES
MUTANTS
OXIDASES
OXIDOREDUCTASES
RESIDUES
RESOLUTION
STREPTOCOCCUS
SUBSTRATES
national synchrotron light source