Understanding the thermal [1s,5s] hydrogen shift isomerization of ocimene

Chamorro, Eduardo; Ruíz, Pablo; Quíjano, Jairo; Luna, Diana Leidy Manrique; Restrepo, Laura; Zuluaga, Sandra; Duque-Noreña, Mario

doi:10.1007/s00894-014-2390-6

Cited by 5 publications

(1 citation statement)

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“…S15 , Supplementary Material online). While the presence of neo-allo-ocimene isomers in both the commercial standard and the samples from mutant lines are almost certainly due to conversion from beta-ocimene due to thermal desorption of volatiles from the SPME fiber ( Chamorro etal. 2014 ) ( supplementary figs.…”

Section: Resultsmentioning

confidence: 99%

In Planta Recapitulation of Isoprene Synthase Evolution from Ocimene Synthases

Alarcón

et al. 2017

Molecular Biology and Evolution

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Isoprene is the most abundant biogenic volatile hydrocarbon compound naturally emitted by plants and plays a major role in atmospheric chemistry. It has been proposed that isoprene synthases (IspS) may readily evolve from other terpene synthases, but this hypothesis has not been experimentally investigated. We isolated and functionally validated in Arabidopsis the first isoprene synthase gene, AdoIspS, from a monocotyledonous species (Arundo donax L., Poaceae). Phylogenetic reconstruction indicates that AdoIspS and dicots isoprene synthases most likely originated by parallel evolution from TPS-b monoterpene synthases. Site-directed mutagenesis demonstrated invivo the functional and evolutionary relevance of the residues considered diagnostic for IspS function. One of these positions was identified by saturating mutagenesis as a major determinant of substrate specificity in AdoIspS able to cause invivo a dramatic change in total volatile emission from hemi- to monoterpenes and supporting evolution of isoprene synthases from ocimene synthases. The mechanism responsible for IspS neofunctionalization by active site size modulation by a single amino acid mutation demonstrated in this study might be general, as the very same amino acidic position is implicated in the parallel evolution of different short-chain terpene synthases from both angiosperms and gymnosperms. Based on these results, we present a model reconciling in a unified conceptual framework the apparently contrasting patterns previously observed for isoprene synthase evolution in plants. These results indicate that parallel evolution may be driven by relatively simple biophysical constraints, and illustrate the intimate molecular evolutionary links between the structural and functional bases of traits with global relevance.

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Section: Resultsmentioning

confidence: 99%