The conformation of some site-specific inhibitors of the ring contraction step in gibberellin plant hormone biosynthesis

Abstract

The X-ray crystal structures are reported for methyl ent-7α-hydroxykaur-16-en-19-oate (3) and for two inhibitors of the ring contraction of the corresponding acid (1) to gibberellin A₁₂ 7-aldehyde (4) by Gibberella fujikuroi. The superimposition of these structures is described and the possible relationship of this to the steric requirements for the biosynthetic ring contraction are discussed.