Sunday, April 29, 2007

A new nitrilase from Bradyrhizobium japonicum USDA 110: Gene cloning, biochemical characterization and substrate specificity

Ling Hua, Chandrani Mukherjee, Dunming Zhu, Beatriz, E. Rios, and Edward, R. Biehl. Chemistry, Southern Methodist University, 3215 Danile Ave., Fondren Science Building Rm231, Dallas, TX 75275

Nitrilase-catalyzed hydrolysis organocyanides (nitriles) to carboxylic acids offers a “greener” alternative to the traditional chemical methods, because this ecofriendly biotransformation allows clean and mild synthesis with high yield and selectivity.1-9 However, many of the known nitrilases possess considerable disadvantages such as low stability or selectivity. This prevents the industrial application of nitrilases, and there is thus a constant demand for new nitrilases.10-12 The rapidly growing genome sequence data obtained in the course of genome projects offers a tremendous opportunity for rapid discovery of new enzyme catalysts. An interesting putative nitrilase gene (blr3397) was identified in Bradyrhizobium japonicum USDA110. As part of our effort to develop an effective nitrilase catalyst tool-box, this putative nitrilase gene was cloned and expressed in E. coli, the encoded protein was purified and characterized. The substrate specificity of this nitrilase was also evaluated towards a variety of nitriles with diverse structures.