Open AccessPyridoxal-5′-phosphate-dependent alkyl transfer in nucleoside antibiotic biosynthesis
Author(s) -
Zheng Cui,
Jonathan Overbay,
Xiachang Wang,
Xiaodong Liu,
Yinan Zhang,
Minakshi Bhardwaj,
Anke Lemke,
Daniel D. Wiegmann,
Giuliairo,
Jon S. Thorson,
Christian Ducho,
Steven G. Van Lanen
Publication year - 2020
Publication title -
nature chemical biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.412
H-Index - 216
eISSN - 1552-4469
pISSN - 1552-4450
DOI - 10.1038/s41589-020-0548-3
Subject(s) - chemistry , nucleoside , stereochemistry , disaccharide , biosynthesis , nucleotide , pyridoxal , alkyl , glycosidic bond , biochemistry , phosphate , enzyme , organic chemistry , gene
Several nucleoside antibiotics are structurally characterized by a 5″-amino-5″-deoxyribose (ADR) appended via a glycosidic bond to a high-carbon sugar nucleoside (5'S,6'S)-5'-C-glycyluridine (GlyU). GlyU is further modified with an N-alkylamine linker, the biosynthetic origin of which has yet to be established. By using a combination of feeding experiments with isotopically labeled precursors and characterization of recombinant proteins from multiple pathways, the biosynthetic mechanism for N-alkylamine installation for ADR-GlyU-containing nucleoside antibiotics has been uncovered. The data reveal S-adenosyl-L-methionine (AdoMet) as the direct precursor of the N-alkylamine, but, unlike conventional AdoMet- or decarboxylated AdoMet-dependent alkyltransferases, the reaction is catalyzed by a pyridoxal-5'-phosphate-dependent aminobutyryltransferase (ABTase) using a stepwise γ-replacement mechanism that couples γ-elimination of AdoMet with aza-γ-addition onto the disaccharide alkyl acceptor. In addition to using a conceptually different strategy for AdoMet-dependent alkylation, the newly discovered ABTases require a phosphorylated disaccharide alkyl acceptor, revealing a cryptic intermediate in the biosynthetic pathway.