Galactaro δ-lactone isomerase: lactone isomerization by a member of the amidohydrolase superfamily.
Agrobacterium tumefaciens strain C58 can utilize d-galacturonate as a sole source of carbon via a pathway in which the first step is oxidation of d-galacturonate to D-galactaro-1,5-lactone. We have identified a novel enzyme, D-galactarolactone isomerase (GLI), that catalyzes the isomerizaton of D-galactaro-1,5-lactone to D-galactaro-1,4-lactone. GLI, a member of the functionally diverse amidohydrolase superfamily, is a homologue of LigI that catalyzes the hydrolysis of 2-pyrone-4,6-dicarboxylate in lignin degradation. The ability of GLI to catalyze lactone isomerization instead of hydrolysis can be explained by the absence of the general basic catalysis used by 2-pyrone-4,6-dicarboxylate lactonase.
Department of Biochemistry, ‡Department of Chemistry, and §Institute for Genomic Biology, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States.
Jason T
JT
Bouvier
Fiona P
FP
Groninger-Poe
Matthew
M
Vetting
Steven C
SC
Almo
John A
JA
Gerlt
D016960:Agrobacterium tumefaciens / Q000201:enzymology*; D000581:Amidohydrolases / Q000737:chemistry*; D001426:Bacterial Proteins / Q000737:chemistry*; D007535:Isomerases / Q000737:chemistry*; D007536:Isomerism; D007783:Lactones / Q000737:chemistry*; D008958:Models, Molecular; D011487:Protein Conformation
D001426:Bacterial Proteins; D007783:Lactones; D000581:Amidohydrolases; D007535:Isomerases