Functional analysis of phenylalanine 365 in hopene synthase, a conserved amino acid in the families of squalene and oxidosqualene cyclases†

Two bicyclic products were accumulated by the mutant F365A, showing the amino acid residue is located close to the transient C-8 carbocation intermediate in the active site cavity; the mutants of F365Y and F365W significantly accelerated the cyclization reaction at low temperatures.