X-ray diffraction structure of a cell-wall invertase from Arabidopsis thaliana.
Cell-wall invertases play crucial roles during plant development. They hydrolyse sucrose into its fructose and glucose subunits by cleavage of the alpha1-beta2 glycosidic bond. Here, the structure of the Arabidopsis thaliana cell-wall invertase 1 (AtcwINV1; gene accession code At3g13790) is described at a resolution of 2.15 A. The structure comprises an N-terminal fivefold beta-propeller domain followed by a C-terminal domain formed by two beta-sheets. The active site is positioned in the fivefold beta-propeller domain, containing the nucleophile Asp23 and the acid/base catalyst Glu203 of the double-displacement enzymatic reaction. The function of the C-terminal domain remains unknown. Unlike in other GH 32 family enzyme structures known to date, in AtcwINV1 the cleft formed between both domains is blocked by Asn299-linked carbohydrates. A preliminary site-directed mutagenesis experiment (Asn299Asp) removed the glycosyl chain but did not alter the activity profile of the enzyme.
Verhaest
Maureen
M
Laboratorium voor Biokristallografie, Faculteit Farmaceutische Wetenschappen, K. U. Leuven, Herestraat 49, O&N II, Bus 822, B-3000 Leuven, Belgium.
Lammens
Willem
W
Le Roy
Katrien
K
De Coninck
Barbara
B
De Ranter
Camiel J
CJ
Van Laere
André
A
Van den Ende
Wim
W
Rabijns
Anja
A
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000201:enzymology*; D029681:Arabidopsis Proteins / Q000737:chemistry* / Q000378:metabolism; D001216:Asparagine / Q000737:chemistry; D001665:Binding Sites; D002241:Carbohydrates; D002473:Cell Wall / Q000201:enzymology*; D006026:Glycoside Hydrolases / Q000378:metabolism; D006860:Hydrogen Bonding; D008958:Models, Molecular; D008969:Molecular Sequence Data; D050505:Mutant Proteins / Q000378:metabolism; D017510:Protein Folding; D017433:Protein Structure, Secondary; D013379:Substrate Specificity; D014961:X-Ray Diffraction; D043324:beta-Fructofuranosidase / Q000737:chemistry* / Q000378:metabolism
D029681:Arabidopsis Proteins; D002241:Carbohydrates; D050505:Mutant Proteins; D001216:Asparagine; D006026:Glycoside Hydrolases; C517207:Inv1 protein, Arabidopsis; D043324:beta-Fructofuranosidase; C044118:fructan beta-fructosidase