Squalene-hopene cyclases-evolution, dynamics and catalytic scope.

Syrén PO, Henche S, Eichler A, Nestl BM, Hauer B

Curr. Opin. Struct. Biol. 41 (-) 73-82 [2016-12-00; online 2016-06-20]

Herein we highlight recent mechanistic findings on the impact of solvent dynamics on catalysis displayed by squalene-hopene cyclases (SHCs). These fascinating biocatalysts that appeared early during the evolution of terpene biosynthetic machineries exploit a catalytic aspartic acid donating the anti-oriented proton to the terminal CC double bond of pre-folded isoprenoid substrates. We review how the unusual strength of this Brønsted acid can be used to harness a plethora of non-natural protonation-driven reactions in a plastic enzyme fold. Moreover, recent results underline how the reaction termination by deprotonation or water addition is governed by the spatial location of water in the active site. Site-directed mutagenesis of amino acids located in the hydrophobic binding pocket allows for the generation of novel catalytic function by active site reshaping with relatively small enzyme libraries. A deepened understanding of triterpene cyclase dynamics in concert with chemical expertise thus have a great potential to allow for the biocatalytic manufacturing of tailored building bricks that would expand the chemical repertoire currently found in nature.

Affiliated researcher

PubMed 27336183

DOI 10.1016/j.sbi.2016.05.019

Crossref 10.1016/j.sbi.2016.05.019

pii: S0959-440X(16)30054-9