Lactococcus lactis dihydroorotate dehydrogenase A mutants reveal important facets of the enzymatic functionNorager, S., Arent, S., Bjornberg, O., Ottosen, M., Lo Leggio, L., Jensen, K.F., Larsen, S.
(2003) J.Biol.Chem. 278: 28812-28822
- PubMed: 12732650
- DOI: 10.1074/jbc.M303767200
- Primary Citation of Related Structures:  1JQV, 1JRB, 1JRC, 1JUB, 1JUE, 1OVD
- PubMed Abstract:
- The crystal structure of Lactococcus lactis dihydroorotate dehydrogenase A complexed with the enzyme reaction product throws light on its enzymatic function
Rowland, P.,Bjornberg, O.,Nielsen, F.S.,Jensen, K.F.,Larsen, S.
(1998) Protein Sci. 7: 1269
- Purification and characterisation of dihydroorotate dehydrogenase A from Lactococcus lactis, crystallisation and preliminary X-ray diffraction studies of the enzyme
Nielsen, F.S.,Rowland, P.,Larsen, S.,Jensen, K.F.
(1996) Protein Sci. 5: 852
- Active site of dihydroorotate dehydrogenase A from Lactococcus lactis investigated by chemical modification and mutagenesis
Bjornberg, O.,Rowland, P.,Larsen, S.,Jensen, K.F.
(1997) Biochemistry 36: 16197
- The crystal structure of the flavin containing enzyme dihydroorotate dehydrogenase A from Lactococcus lactis
Rowland, P.,Nielsen, F.S.,Jensen, K.F.,Larsen, S.
(1997) Structure 5: 239
Dihydroorotate dehydrogenases (DHODs) are flavoenzymes catalyzing the oxidation of (S)-dihydroorotate to orotate in the biosynthesis of UMP, the precursor of all other pyrimidine nucleotides. On the basis of sequence, DHODs can be divided into two cl ...
Dihydroorotate dehydrogenases (DHODs) are flavoenzymes catalyzing the oxidation of (S)-dihydroorotate to orotate in the biosynthesis of UMP, the precursor of all other pyrimidine nucleotides. On the basis of sequence, DHODs can be divided into two classes, class 1, further divided in subclasses 1A and 1B, and class 2. This division corresponds to differences in cellular location and the nature of the electron acceptor. Herein we report a study of Lactococcus lactis DHODA, a representative of the class 1A enzymes. Based on the DHODA structure we selected seven residues that are highly conserved between both main classes of DHODs as well as three residues representing surface charges close to the active site for site-directed mutagenesis. The availability of both kinetic and structural data on the mutant enzymes allowed us to define the roles individual structural segments play in catalysis. We have also structurally proven the presence of an open active site loop in DHODA and obtained information about the interactions that control movements of loops around the active site. Furthermore, in one mutant structure we observed differences between the two monomers of the dimer, confirming an apparent asymmetry between the two substrate binding sites that was indicated by the kinetic results.
Centre for Crystallographic Studies, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark.