ja510489j_si_001.pdf (600.73 kB)
Adenylation and S‑Methylation of Cysteine by the Bifunctional Enzyme TioN in Thiocoraline Biosynthesis
journal contribution
posted on 2014-12-10, 00:00 authored by Ahmad
H. Al-Mestarihi, Germán Villamizar, Javier Fernández, Olga E. Zolova, Felipe Lombó, Sylvie Garneau-TsodikovaThe antitumor agent thiocoraline
is a nonribosomally biosynthesized
bisintercalator natural product, which contains in its peptidic backbone
two S-methylated l-cysteine residues. S-Methylation occurs very rarely in nature, and is observed
extremely rarely in nonribosomal peptide scaffolds. We have proposed
that during thiocoraline biosynthesis, TioN, a stand-alone adenylation
domain interrupted by the S-adenosyl-l-methionine
binding region of a methyltransferase enzyme, is capable of performing
two functions: the adenylation and S-methylation
of l-cysteine. Herein, by preparation of knockouts of TioN
and its MbtH-like protein partner TioT, we confirmed their role in
thiocoraline biosynthesis. We also co-expressed recombinant TioN and
TioT and biochemically investigated three potential pathways involving
activation, methylation, and loading of l-cysteine onto the
TioN partner thiolation domain, TioS(T4). The valuable
insights gained into the pathway(s) followed for the production of S-Me-l-Cys-S-TioS(T4) will serve as a guide for the development of novel engineered interrupted
adenylation enzymes for combinatorial biosynthesis.