Scheme 1.

The engineering of a direct sulfhydrylation pathway in E. coli methionine metabolism. Scheme of the altered l‐methionine metabolism in engineered MDS15 and MDS15A E. coli strains where metA and metE genes have been knocked out; direct sulfhydrylation pathway enzymes cgHSAT and cgOAHSS were introduced on a pSEVA26′glnS plasmid for production of Aha. The E. coli strain JW3973 (Met‐auxotrophy control) has only the metA gene knocked out. The trans‐sulfuration pathway is shown in brown, direct sulfhydrylation pathway in blue, L‐azidohomoalanine production in green.