Structural insights into a maleylpyruvate hydrolase from sphingobium sp. SYK-6, a bacterium degrading lignin-derived aryls.

ABSTRACT

Sphingobium sp. strain SYK-6, an aerobic gram-negative bacillus found in soil, is known for utilizing lignin-derived monoaryls and biaryls as carbon sources and degrading aromatic compounds. The Sphingobium sp. strain SYK-6 genome contains three genes involved in salicylate catabolism SLG_11260, SLG_11270, and SLG_11280. Here, we report that the gene product of SLG_11280 functions as a maleylpyruvate hydrolase (SsMPH) with Km and Kcat values of 166.2 µM and 3.76 min-1, respectively. This study also reveals the crystal structures of both the apo and pyruvate-manganese ion-bound SsMPH, which revealed that like other fumarylacetoacetate hydrolases, SsMPH dimerizes and has nine unique 310-helices. Molecular docking studies of maleylpyruvate also revealed the likely binding mode of SsMPH and its substrate.