Functional analysis of Phe605, a conserved aromatic amino acid in squalene–hopene cyclasesElectronic supplementary information (ESI) available: EIMS spectra and NMR assignments of products 3–12. See http://www.rsc.org/suppdata/cc/b0/b004129g

Abstract

Incubation of squalene with the site-directed mutant F605A of squalene–hopene cyclase from Alicyclobacillus acidocaldarius yielded many triterpenes consisting of the 6/6/5-fused tri-, 6/6/6/5-fused tetra-, and 6/6/6/6/5-fused pentacyclic skeletons, the function of F605 being assignable for facilitating the ring expansion and for stabilizing the hopanyl C22-cation, possibly via cation-π interactions.