A multifunctional hybrid glycosyl hydrolase discovered in an uncultured microbial consortium from ruminant gut.
A unique multifunctional glycosyl hydrolase was discovered by screening an environmental DNA library prepared from a microbial consortium collected from cow rumen. The protein consists of two adjacent catalytic domains. Sequence analysis predicted that one domain conforms to glycosyl hydrolase family 5 and the other to family 26. The enzyme is active on several different beta-linked substrates and possesses mannanase, xylanase, and glucanase activities. Site-directed mutagenesis studies on the catalytic residues confirmed the presence of two functionally independent catalytic domains. Using site-specific mutations, it was shown that one catalytic site hydrolyzes beta-1,4-linked mannan substrates, while the second catalytic site hydrolyzes beta-1,4-linked xylan and beta-1,4-linked glucan substrates. Polysaccharide Analysis using Carbohydrate gel Electrophoresis (PACE) also confirmed that the enzyme has discrete domains for binding and hydrolysis of glucan- and mannan-linked polysaccharides. Such multifunctional enzymes have many potential industrial applications in plant processing, including biomass saccharification, animal feed nutritional enhancement, textile, and pulp and paper processing.
Palackal
Nisha
N
Diversa Corporation, 4955 Directors Place, San Diego, CA 92121, USA.
Lyon
Christopher S
CS
Zaidi
Seema
S
Luginbühl
Peter
P
Dupree
Paul
P
Goubet
Florence
F
Macomber
John L
JL
Short
Jay M
JM
Hazlewood
Geoffrey P
GP
Robertson
Dan E
DE
Steer
Brian A
BA
D000818:Animals; D001483:Base Sequence; D002417:Cattle; D015723:Gene Library; D005936:Glucans / Q000378:metabolism; D006026:Glycoside Hydrolases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D007218:Industrial Microbiology; D008351:Mannans / Q000378:metabolism; D008969:Molecular Sequence Data; D009097:Multienzyme Complexes / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D016297:Mutagenesis, Site-Directed; D012417:Rumen / Q000382:microbiology*; D017422:Sequence Analysis, DNA; D014990:Xylans / Q000378:metabolism
D005936:Glucans; D008351:Mannans; D009097:Multienzyme Complexes; D014990:Xylans; D006026:Glycoside Hydrolases