Characterization of a Thermobifida fusca beta-1,3-glucanase (Lam81A) with a potential role in plant biomass degradation.
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 (http://afmb.cnrs-mrs.fr/CAZY/) 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.
McGrath
Colleen E
CE
Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853, USA.
Wilson
David B
DB
D000192:Actinomycetales / Q000201:enzymology*; D001483:Base Sequence; D018533:Biomass; D002855:Chromatography, Thin Layer; D017931:DNA Primers; D004591:Electrophoresis, Polyacrylamide Gel; D004693:Glucan Endo-1,3-beta-D-Glucosidase / Q000378:metabolism*; D019906:Nuclear Magnetic Resonance, Biomolecular; D010944:Plants / Q000378:metabolism*; D016133:Polymerase Chain Reaction
D017931:DNA Primers; D004693:Glucan Endo-1,3-beta-D-Glucosidase