Characterization of a Thermobifida fusca beta-1,3-glucanase (Lam81A) with a potential role in plant biomass degradation.

McGrath CE, Wilson DB
Biochemistry. 2006 45 (47): 14094-100

PMID: 17115704 · DOI:10.1021/bi061757r

Thermobifida fusca is a filamentous soil bacterium that plays a major role in the breakdown of plant biomass. In this paper, we report the cloning, expression, purification, and characterization of the T. fusca enzyme, Lam81A. The Carbohydrate Active Enzymes Database ( indicates that Lam81A belongs to a relatively uncharacterized family of beta-1,3-glucanases, family GH-81 [Coutinho, P. M., and Henrissat, B. (1999) in Recent Advances in Carbohydrate Bioengineering (Gilbert, H. J., Davies, G., Henrissat, B., and Svensson, B., Eds.) pp 3-12, The Royal Society of Chemistry, Cambridge, U.K.]. Microarray analysis suggests that Lam81A plays a role in biomass degradation, where its natural substrate may be the plant cell wall polysaccharide, callose, which is a polymer of beta-1,3-linked glucose. Characterization of Lam81A has shown that the enzyme is specific for beta-1,3-linked glucose polysaccharides, is endohydrolytic, and utilizes an inverting mechanism for substrate hydrolysis. In addition, the enzyme has a broad pH optimum from 5.5 to 10, a temperature optimum of 50 degrees C, and demonstrates substrate inhibition, as well as showing a high basal level of expression.

MeSH Terms (10)

Actinomycetales Base Sequence Biomass Chromatography, Thin Layer DNA Primers Electrophoresis, Polyacrylamide Gel Glucan Endo-1,3-beta-D-Glucosidase Nuclear Magnetic Resonance, Biomolecular Plants Polymerase Chain Reaction

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