1.Structural and Affinity Determinants in the Interaction between Alcohol Acyltransferase from F. x ananassa and Several Alcohol Substrates: A Computational Study.
Navarro-Retamal C1, Gaete-Eastman C2, Herrera R2, Caballero J1, Alzate-Morales JH1. PLoS One. 2016 Apr 14;11(4):e0153057. doi: 10.1371/journal.pone.0153057.
Aroma and flavor are important factors of fruit quality and consumer preference. The specific pattern of aroma is generated during ripening by the accumulation of volatiles compounds, which are mainly esters. Alcohol acyltransferase (AAT) (EC 2.3.1.84) catalyzes the esterification reaction of aliphatic and aromatic alcohols and acyl-CoA into esters in fruits and flowers. In Fragaria x ananassa, there are different volatiles compounds that are obtained from different alcohol precursors, where octanol and hexanol are the most abundant during fruit ripening. At present, there is not structural evidence about the mechanism used by the AAT to synthesize esters. Experimental data attribute the kinetic role of this enzyme to 2 amino acidic residues in a highly conserved motif (HXXXD) that is located in the middle of the protein. With the aim to understand the molecular and energetic aspects of volatiles compound production from F. x ananassa, we first studied the binding modes of a series of alcohols, and also different acyl-CoA substrates, in a molecular model of alcohol acyltransferase from Fragaria x ananassa (SAAT) using molecular docking.
2.PTR-MS Characterization of VOCs Associated with Commercial Aromatic Bakery Yeasts of Wine and Beer Origin.
Capozzi V1,2,3, Makhoul S4,5,6, Aprea E7, Romano A8, Cappellin L9, Sanchez Jimena A10, Spano G11, Gasperi F12, Scampicchio M13, Biasioli F14. Molecules. 2016 Apr 12;21(4). pii: E483.
In light of the increasing attention towards "green" solutions to improve food quality, the use of aromatic-enhancing microorganisms offers the advantage to be a natural and sustainable solution that did not negatively influence the list of ingredients. In this study, we characterize, for the first time, volatile organic compounds (VOCs) associated with aromatic bakery yeasts. Three commercial bakery starter cultures, respectively formulated with three Saccharomyces cerevisiae strains, isolated from white wine, red wine, and beer, were monitored by a proton-transfer-reaction time-of-flight mass spectrometer (PTR-ToF-MS), a direct injection analytical technique for detecting volatile organic compounds with high sensitivity (VOCs). Two ethanol-related peaks (m/z 65.059 and 75.080) described qualitative differences in fermentative performances. The release of compounds associated to the peaks at m/z 89.059, m/z 103.075, and m/z 117.093, tentatively identified as acetoin and esters, are coherent with claimed flavor properties of the investigated strains.
3.Neuroprotective Properties of Compounds Extracted from Dianthus superbus L. against Glutamate-induced Cell Death in HT22 Cells.
Yun BR1, Yang HJ1, Weon JB1, Lee J1, Eom MR1, Ma CJ2. Pharmacogn Mag. 2016 Apr-Jun;12(46):109-13. doi: 10.4103/0973-1296.177905.
BACKGROUND: Dianthus superbus L. has been used in Chinese herbal medicine as a diuretic and anti-inflammatory agent.
4.Asymmetric Syntheses of (+)-Preussin B, the C(2)-Epimer of (-)-Preussin B, and 3-Deoxy-(+)-preussin B.
Buchman M, Csatayová K, Davies SG, Fletcher AM, Houlsby IT, Roberts PM, Rowe SM, Thomson JE. J Org Chem. 2016 Apr 14. [Epub ahead of print]
Efficient de novo asymmetric syntheses of (+)-preussin B, the C(2)-epimer of (-)-preussin B, and 3-deoxy-(+)-preussin B have been developed, using the diastereoselective conjugate addition of lithium (S)-N-benzyl-N-(alpha-methylbenzyl)amide to tert-butyl 4-phenylbut-2-enoate and diastereoselective, reductive cyclisation of gamma-amino ketones as the key steps to set the stereochemistry. Conjugate addition followed by enolate protonation generated the corresponding beta-amino ester. Homologation using the ester functionality as a synthetic handle gave the corresponding gamma-amino ketone. Hydrogenolytic N-debenzylation was accompanied by diastereoselective, reductive cyclisation in situ; reductive N-methylation then gave 3-deoxy-(+)-preussin B as the major diastereoisomeric product. Meanwhile, the same conjugate addition but followed by enolate oxidation with (+)-camphorsulfonyloxaziridine (CSO) gave the corresponding anti-alpha-hydroxy-beta-amino ester.
