Download MendeleyStereochemistry in the Reaction of themyo-Inositol Phosphate Synthase Ortholog Ari2 during Aristeromycin Biosynthesis.
Kudo, F., Tsunoda, T., Yamaguchi, K., Miyanaga, A., Eguchi, T.(2019) Biochemistry 58: 5112-5116
- PubMed: 31825604
- DOI: https://doi.org/10.1021/acs.biochem.9b00981
- Primary Citation of Related Structures:
6K96 - PubMed Abstract:
The myo -inositol-1-phosphate synthase (MIPS) ortholog Ari2, which is encoded in the aristeromycin biosynthetic gene cluster, catalyzes the formation of five-membered cyclitol phosphate using d-fructose 6-phosphate (F6P) as a substrate. To understand the stereochemistry during the Ari2 reaction in vivo , we carried out feeding experiments with (6 S )-d-[6- 2 H 1 ]- and (6 R )-d-[6- 2 H 1 ]glucose in the aristeromycin-producing strain Streptomyces citricolor . We observed retention of the 2 H atom of (6 S )-d-[6- 2 H 1 ]glucose and no incorporation of the 2 H atom from (6 R )-d-[6- 2 H 1 ]glucose in aristeromycin. This indicates that Ari2 abstracts the pro-R proton at C6 of F6P after oxidation of C5-OH by nicotinamide adenine dinucleotide (NAD + ) to generate the enolate intermediate, which then attacks the C2 ketone to form the C-C bond via aldol-type condensation. The reaction of Ari2 with (6 S )-d-[6- 2 H 1 ]- and (6 R )-d-[6- 2 H 1 ]F6P in vitro exhibited identical stereochemistry compared with that observed during the feeding experiments. Furthermore, analysis of the crystal structure of Ari2, including NAD + as a ligand, revealed the active site of Ari2 to be similar to that of MIPS of Mycobacterium tuberculosis , supporting the similarity of the reaction mechanisms of Ari2 and MIPS.
Organizational Affiliation:
Department of Chemistry , Tokyo Institute of Technology , 2-12-1, O-okayama , Meguro-ku, Tokyo 152-8551 , Japan.
