Identification and characterization of a novel methionine γ-lyase gene from deep-sea sediment metagenomic library

A putative methionine γ-lyase (MGL) gene was identified from a deep-sea sediment metagenomic library. The gene (mgl_deepsea), consisting of 1,281 nucleotides, shares a high degree of sequence identity (67%) with the mgl gene from genus Idiomarina. The mgl gene was cloned and overexpressed in Escherichia coli. The expressed product of the gene has a molecular mass of 46 kDa as determined by SDS–PAGE. The recombinant enzyme (rMGL) was able to catalyse the lysis of l-methionine and DL-homocysteine, but not l-cysteine and l-cystine. The optimal temperature of the rMGL was 60°C and pH was 9.5. This is the first report to identify and characterize the mgl gene from a deep-sea metagenomic library.