Structural modeling of glucanase-substrate complexes suggests a conserved tyrosine is involved in carbohydrate recognition in plant 1,3-1,4-beta-D-glucanases.
Glycosyl hydrolase family 16 (GHF16) truncated Fibrobacter succinogenes (TFs) and GHF17 barley 1,3-1,4-beta-D-glucanases (beta-glucanases) possess different structural folds, beta-jellyroll and (beta/alpha)8, although they both catalyze the specific hydrolysis of beta-1,4 glycosidic bonds adjacent to beta-1,3 linkages in mixed beta-1,3 and beta-1,4 beta-D-glucans or lichenan. Differences in the active site region residues of TFs beta-glucanase and barley beta-glucanase create binding site topographies that require different substrate conformations. In contrast to barley beta-glucanase, TFs beta-glucanase possesses a unique and compact active site. The structural analysis results suggest that the tyrosine residue, which is conserved in all known 1,3-1,4-beta-D-glucanases, is involved in the recognition of mixed beta-1,3 and beta-1,4 linked polysaccharide.
Tsai
Li-Chu
LC
Department of Molecular Science and Engineering, National Taipei University of Technology, Taipei, Taiwan. lichu@ntut.edu.tw
Chen
Yi-Ning
YN
Shyur
Lie-Fen
LF
D000595:Amino Acid Sequence; D050260:Carbohydrate Metabolism; D020134:Catalytic Domain; D044644:Endo-1,3(4)-beta-Glucanase / Q000737:chemistry / Q000378:metabolism*; D008958:Models, Molecular; D008961:Models, Structural; D008969:Molecular Sequence Data; D010944:Plants / Q000201:enzymology*; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity; D014443:Tyrosine / Q000737:chemistry / Q000378:metabolism*
D014443:Tyrosine; D044644:Endo-1,3(4)-beta-Glucanase