Structural basis for substrate specificity of l-methionine decarboxylase

Atsushi Okawa, Tomoo Shiba, Masaya Hayashi, Yuki Onoue, Masaki Murota, Dan Sato, Junko Inagaki, Takashi Tamura, Shigeharu Harada, Kenji Inagaki

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)


l -Methionine decarboxylase (MetDC) from Streptomyces sp. 590 is a vitamin B6-dependent enzyme and catalyzes the non-oxidative decarboxylation of l -methionine to produce 3-methylthiopropylamine and carbon dioxide. We present here the crystal structures of the ligand-free form of MetDC and of several enzymatic reaction intermediates. Group II amino acid decarboxylases have many residues in common around the active site but the residues surrounding the side chain of the substrate differ. Based on information obtained from the crystal structure, and mutational and biochemical experiments, we propose a key role for Gln64 in determining the substrate specificity of MetDC, and for Tyr421 as the acid catalyst that participates in protonation after the decarboxylation reaction.

Original languageEnglish
Pages (from-to)663-677
Number of pages15
JournalProtein Science
Issue number3
Publication statusPublished - Mar 2021


  • Streptomyces
  • amino acid
  • amino acid decarboxylase
  • crystal structure
  • l -methionine decarboxylase
  • pyridoxal 5′-phosphate
  • reaction mechanism
  • site-directed mutagenesis
  • substrate specificity
  • vitamin B - dependent enzyme

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology


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