TY - JOUR
T1 - Site-directed mutagenesis study of the three catalic residues of the fructosyltransferases of Lactobacillus reuteri 121.
AU - Ozimek, L.K.
AU - van Huijum, S.A.F.T.
AU - van Koningsveld, G.A.
AU - Maarel, M.J.E.J.
AU - van Geel-Schutten, G.H.
AU - Dijkhuizen, L.
PY - 2004
Y1 - 2004
N2 - Bacterial fructosyltransferases (FTFs) are retaining-type glycosidases that belong to family 68 of glycoside hydrolases. Recently, the high-resolution 3D structure of the Bacillus subtilis levansucrase has been solved [Meng, G. and Futterer, K., Nat. Struct. Biol. 10 (2003) 935–941]. Based on this structure, the catalytic nucleophile, general acid/base catalyst, and transition state stabilizer were identified. However, a detailed characterization of site-directed mutants of the catalytic nucleophile has not been presented for any FTF enzyme. We have constructed site-directed mutants of the three putative catalytic residues of the Lactobacillus reuteri 121 levansucrase and inulosucrase and characterized the mutant proteins. Changing the putative catalytic nucleophiles D272 (inulosucrase) and D249 (levansucrase) into their amido counterparts resulted in a 1.5–4×105 times reduction of total sucrase activity.
AB - Bacterial fructosyltransferases (FTFs) are retaining-type glycosidases that belong to family 68 of glycoside hydrolases. Recently, the high-resolution 3D structure of the Bacillus subtilis levansucrase has been solved [Meng, G. and Futterer, K., Nat. Struct. Biol. 10 (2003) 935–941]. Based on this structure, the catalytic nucleophile, general acid/base catalyst, and transition state stabilizer were identified. However, a detailed characterization of site-directed mutants of the catalytic nucleophile has not been presented for any FTF enzyme. We have constructed site-directed mutants of the three putative catalytic residues of the Lactobacillus reuteri 121 levansucrase and inulosucrase and characterized the mutant proteins. Changing the putative catalytic nucleophiles D272 (inulosucrase) and D249 (levansucrase) into their amido counterparts resulted in a 1.5–4×105 times reduction of total sucrase activity.
KW - acid-residues
KW - levansucrase
KW - reuteri
U2 - 10.1016/S0014-5793(04)00085-7
DO - 10.1016/S0014-5793(04)00085-7
M3 - Article
SN - 0014-5793
VL - 560
SP - 131
EP - 133
JO - FEBS Letters
JF - FEBS Letters
IS - 1-3
ER -