Abstract.
A β-mannanase gene (manA) was isolated from the extremely thermophilic bacterium Dictyoglomus thermophilum Rt46B.1. ManA is a single-domain enzyme related to one group of β-mannanases (glycosyl hydrolase family 26). The manA gene was expressed in the heat-inducible vector pJLA602 and the expression product, ManA, purified to homogeneity. The recombinant ManA is a monomeric enzyme with a molecular mass of 40 kDa and an optimal temperature and pH for activity of 80°C and 5.0. In the absence of substrate, the enzyme showed no loss of activity at 80°C over 16 h, while at 90°C the enzyme had a half-life of 5.4 min. Hydrolysis of the galactomannan locust bean gum (LBG) by purified ManA released mainly mannose, mannobiose, and mannotriose, confirming that ManA is an endo-acting β-mannanase. Sequence comparisons with related β-mannanases has allowed the design of consensus PCR primers for the identification and isolation of related genes.
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Received: 7 June 1999 / Accepted: 6 July 1999
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Gibbs, M., Reeves, R., Sunna, A. et al. Sequencing and Expression of a β-Mannanase Gene from the Extreme Thermophile Dictyoglomus thermophilum Rt46B.1, and Characteristics of the Recombinant Enzyme. Curr Microbiol 39, 351–357 (1999). https://doi.org/10.1007/s002849900471
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DOI: https://doi.org/10.1007/s002849900471