Computational and in vitro analysis of an HBCD degrading gene DehHZ1 from strain HBCD-sjtu

Abstract

Hexabromocyclododecanes (HBCD), an additive brominated flame retardant, is causing great concern as a result of its extensive use and increasing volumes in different environmental systems. In this study, the HBCD degrading gene dehHZ1 was identified from strain HBCD-sjtu by homology modelling of enzyme DehHZ1 sequence with LinB from strain Sphingobium indicum B90A, an HBCD degrading enzyme. The three dimensional (3D) model structures of enzyme DehHZ1 were obtained. Structure and functional relationship of the enzyme DehHZ1 with compound HBCD was performed using active sites. The HBCD degrading ability of the transformant containing the gene dehHZ1 was observed at 30ºC, pH 7.0 and 200 RPM, in mineral salt medium (MSM) with 0.1 mM HBCD. An intermediate 1, 5, 9-cyclododecatriene (CDT) was recognized based on gas chromatography mass spectrometry analyses after HBCD degradation. These findings may provide new insights into the environment friendly route of HBCD degradation and its conversion into new metabolite.