Background and Aims
Laccase enzymes produced by Botrytis cinerea are involved in the oxidation of phenolic substances during the development of grey mould, which causes significant economic losses. ...The aim of this work was to study the structural and activity characteristics of the laccase enzymes secreted by three B. cinerea strains that are involved in the development of grey mould.
Methods and Results
Laccase enzymes obtained from three B. cinerea strains one reference strain (B05.10) and two strains obtained from two French vineyards (VA612 and RM344) were characterised. Analysis by LC‐QTOF‐MS revealed that the three strains contained a mixture of Laccase‐2‐BcLCC2 and Laccase‐3‐BcLCC7. The structural characteristics of the laccases from the three strains, such as molecular weight and glycosylation degree, were identical. Nevertheless, their catalytic activities were significantly different.
Conclusions
Differences in catalytic activities could be due either to possible differences in the relative amount of Laccase‐2‐BcLCC2 and Laccase‐3‐BcLCC7 produced by each strain or to differences in the glycosidic fraction of the enzymes.
Significance of the Study
The severity of the infection caused by B. cinerea may be not only related to the infection level but also to the strain involved.
In this work, sensations elicited by catechin and procyanidins in comparison with those elicited by gallocatechin and prodelphinidins were evaluated by means of a sensory panel. To obtain further ...insights into the mechanisms of action, molecular dynamics (MD) simulations and saturation transfer difference nuclear magnetic resonance (STD NMR) experiments have been performed. Results showed clear differences between the 2 types of flavanols. Dihydroxylated B-ring flavanols were more astringent, bitter, dry, rough, unripe, and persistent than trihydroxylated B-ring ones. Besides, these last compounds were smoother, more velvety, and viscous. MD simulations and STD NMR experiments support results obtained from tasting panel. MD results suggested that catechin binds to a human salivary proline-rich peptide IB714 faster than gallocatechin and this interaction is maintained longer. IB714 can interact with 2 catechin molecules concurrently while only interacts with 1 gallocatechin molecule. Accordingly, STD NMR experiments showed a greater affinity of catechin than gallocatechin for the peptide (K D = 2.7 and 25.7, respectively). Results indicate that the number of hydroxyl substituents present in B-ring of the flavanic nucleus is decisive for the interaction with salivary proteins and the development of astringency perception.
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