@article{oai:niigata-u.repo.nii.ac.jp:00001562,
 author = {Sato, Tsutomu and Sasahara, Shigehiro and Yamakami, Toshiyuki and Hoshino, Tsutomu},
 issue = {8},
 journal = {Bioscience, Biotechnology, and Biochemistry},
 month = {},
 note = {The functions of Tyr420 and Leu607 were analyzed by constructing various site-directed mutants. The mutation at position 420 into Ala and Gly gave bicyclic α- and γ-polypodatetraene in significant amounts, but with a trace amount of tricyclic malabaricatriene. The kinetic data for and the product distribution of the Y420F mutant indicate that the major function of Tyr420 is to stabilize the 6/6-fused bicyclic cation. Mutation experiments on Leu607 demonstrate that the appropriate steric bulk size at position 607 is required to strongly bind with the product-like conformation formed during the polycyclization process. Introduction of the bulkiest Tip residue into 420 or 607 led to the production of a novel monocyclic triterpene having the (5R, 6R)-1,5,6-trimethylcyclohexene ring, named neoachillapentaene,indicating that the enzymatic cyclization proceeded via a constrained boat structure. Folding of the squalene molecule into a boat conformation by squalene cyclase has not been reported before.},
 pages = {1660--1670},
 title = {Functional analyses of Tyr420 and Leu607 of Alicyclobacillus acidocaldarius squalene-hopene cyclase. Neoachillapentaene, a novel triterpene with the 1, 5, 6-trimethylcyclohexene moiety produced through a folding of the constrained boat structure.},
 volume = {66},
 year = {2002}
}