A lichenase-like family 12 endo-(1-->4)-beta-glucanase from Aspergillus japonicus: study of the substrate specificity and mode of action on beta-glucans in comparison with other glycoside hydrolases.
Using anion-exchange chromatography on Source 15Q followed by hydrophobic interaction chromatography on Source 15 Isopropyl, a lichenase-like endo-(1-->4)-beta-glucanase (BG, 28kDa, pI4.1) was isolated from a culture filtrate of Aspergillus japonicus. The enzyme was highly active against barley beta-glucan and lichenan (263 and 267 U/mg protein) and had much lower activity toward carboxymethylcellulose (3.9 U/mg). The mode of action of the BG on barley beta-glucan and lichenan was studied in comparison with that of Bacillus subtilis lichenase and endo-(1-->4)-beta-glucanases (EG I, II, and III) of Trichoderma reesei. The BG behaved very similar to the bacterial lichenase, except the tri- and tetrasaccharides formed as the end products of beta-glucan hydrolysis with the BG contained the beta-(1-->3)-glucoside linkage at the non-reducing end, while the lichenase-derived oligosaccharides had the beta-(1-->3)-linkage at the reducing end. The BG was characterized by a high amino acid sequence identity to the EG of Aspergillus kawachii (UniProt entry Q12679) from a family 12 of glycoside hydrolases (96% in 162 identified aa residues out of total 223 residues) and also showed lower sequence similarity to the EglA of Aspergillus niger (O74705).
Grishutin
Sergei G
SG
Division of Chemical Enzymology, Department of Chemistry, M. V. Lomonosov Moscow State University, Moscow 119899, Russia.
Gusakov
Alexander V
AV
Dzedzyulya
Ekaterina I
EI
Sinitsyn
Arkady P
AP
D000595:Amino Acid Sequence; D001230:Aspergillus / Q000201:enzymology*; D002480:Cellulase / Q000737:chemistry* / Q000378:metabolism*; D006026:Glycoside Hydrolases / Q000737:chemistry / Q000378:metabolism; D008969:Molecular Sequence Data; D005810:Multigene Family; D016415:Sequence Alignment; D013379:Substrate Specificity / Q000502:physiology; D047071:beta-Glucans / Q000737:chemistry / Q000378:metabolism*
D047071:beta-Glucans; D006026:Glycoside Hydrolases; D002480:Cellulase; C028020:licheninase