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Publication Abstract from PubMed

CalE6 is a previously uncharacterized protein involved in the biosynthesis of calicheamicins in Micromonospora echinospora. It is a pyridoxal-5'-phosphate-dependent enzyme and exhibits high sequence homology to cystathionine gamma-lyases and cystathionine gamma-synthases. However, it was found to be active towards methionine and to convert this amino acid into alpha-ketobutyrate, ammonium, and methanethiol. The crystal structure of the cofactor-bound holoenzyme was resolved at 2.0 A; it contains two active site residues, Gly105 and Val322, specific for methionine gamma-lyases. Modeling of methionine into the active site allows identification of the active site residues responsible for substrate recognition and catalysis. These findings support that CalE6 is a putative methionine gamma-lyase producing methanethiol as a building block in biosynthesis of calicheamicins.

Identification and Characterization of a Methionine gamma-Lyase in the Calicheamicin Biosynthetic Cluster of Micromonospora echinospora.,Song H, Xu R, Guo Z Chembiochem. 2015 Jan 2;16(1):100-9. doi: 10.1002/cbic.201402489. Epub 2014 Nov, 17. PMID:25404066^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.