Halophilic Martelella strain AD-3, isolated from highly saline petroleum-contaminated soil, can efficiently degrade @entity2555 ( @entity2556 ), such as @entity11966 and @entity10517 , in 3-5% salinity. @entity22559 is a key intermediate in the microbial degradation of @entity2556 compounds. However, there is little information on @entity2556 degradation by moderately halophilic bacteria. In this study, a 1,077-bp long gene encoding @entity35005 1,2-dioxygenase (GDO) from a halophilic Martelella strain AD-3 was cloned, sequenced, and expressed in @entity526 . The recombinant enzyme GDO was purified and characterized in detail. By using the @entity14682 isotope experiment and LC-MS analysis, the sources of the two @entity26 atoms added onto maleylpyruvate were identified as @entity4358 and @entity3612 , respectively. The Km and kcat values for @entity22559 were determined to be 26.64    M and 161.29   s(-1), respectively. In addition, optimal GDO activity was observed at 30     C, pH 7.0, and at 12% salinity. Site-directed mutagenesis demonstrated the importance of four highly conserved His residues at positions 155, 157, 167, and 169 for enzyme activity. This finding provides new insights into mechanism and variety of @entity35005 1,2-dioxygenase for @entity2556 degradation in high saline conditions.

Identification and Characterization of a Novel XXXX 1,2-Dioxygenase Gene from a Halophilic Martelella Strain.

@entity22559 :: ('MESH:C010925', 'Chemical') :: ['Gentisic acid', 'gentisic acid'] @entity10517 :: ('MESH:C034020', 'Chemical') :: ['anthracene'] @entity2555 :: ('MESH:D011084', 'Chemical') :: ['polycyclic aromatic hydrocarbons'] @entity4358 :: ('D014867', 'Chemical') :: ['H2O'] @entity26 :: ('MESH:D010100', 'Chemical') :: ['oxygen'] @entity14682 :: ('CHEBI:33815', 'Chemical') :: ['(18)O'] @entity2556 :: ('CHEBI:33848', 'Chemical') :: ['PAHs', 'PAH'] @entity3612 :: ('D013481', 'Chemical') :: ['O2'] @entity35005 :: ('CHEBI:17189', 'Chemical') :: ['gentisate'] @entity526 :: ('562', 'Species') :: ['Escherichia coli'] @entity11966 :: ('MESH:C031181', 'Chemical') :: ['phenanthrene']
@entity35005 :: (CHEBI:17189,Chemical) :: ['Gentisate']
