Substitution of a non-active-site residue located on the T3 loop increased the catalytic efficiency of endo-polygalacturonases

Tu T; Pan X; Meng K; Luo HY; Ma R; Wang Y; Yao B

Process Biochemistry, Vol.51, No.9, 1230-1238, 2016

DOI10.1016/j.procbio.2016.05.020 Export Citation

Substitution of a non-active-site residue located on the T3 loop increased the catalytic efficiency of endo-polygalacturonases

Tu T, Pan X, Meng K, Luo HY, Ma R, Wang Y, Yao B

Endo-polygalacturonases (PGs) of glycosyl hydrolase (GH) family 28 share a right handed parallel beta-helical structure with a cleft formed by T1 and T3 loops. To reveal the effect of non-active-site residues on endo-PG catalysis, Thr113 of Achaetomium sp. endo-PG (PG8fn) located on the T3 loop was substituted. The experimental results indicated that the catalytic efficiency of PG8fn depends on the side-chain structure of residue at position 113, following the order of Glu (negatively charged)

Keywords:Endo-polygalacturonase (endo-PG);Non-active-site residue;Site-directed mutagenesis;Catalytic efficiency;Molecular dynamics (MD)