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Unexpected property of ectoine synthase and its application for synthesis of the engineered compatible solute ADPC
journal contribution
posted on 2023-05-17, 06:17 authored by Witt, EMHJ, Noel DaviesNoel Davies, Galinski, EAA new cyclic amino acid was detected in a deletion mutant of the moderately halophilic bacterium Halomonas elongata deficient in ectoine synthesis. Using mass spectroscopy (MS) and nuclear magnetic resonance (NMR) techniques, the substance was identified as 5-amino-3,4- dihydro-2H-pyrrole-2-carboxylate (ADPC). We were able to demonstrate that ADPC is the product of a side reaction of lone ectoine synthase (EC 4.2.1.108), which forms ADPC by cyclic condensation of glutamine. This reaction was shown to be reversible. Subsequently, a number of ectoine derivatives, in particular 4,5-dihydro-2-methylimidazole-4- carboxylate (DHMICA) and homoectoine, were also shown to be cleaved by ectoine synthase, which is classified as a hydro-lyase. This study thus reports for the first time that ectoine synthase accepts more than one substrate and is a reversible enzyme able to catalyze both the intramolecular condensation into and the hydrolytic cleavage of cyclic amino acid derivatives. As ADPC supports growth of bacteria under salt stress conditions and stabilizes enzymes against freezethaw denaturation, it displays typical properties of compatible solutes. As ADPC has not yet been described as a natural compound, it is presented here as the first man-made compatible solute created through genetic engineering.
History
Publication title
Applied Microbiology and BiotechnologyVolume
91Pagination
113-122ISSN
0175-7598Publisher
Springer-VerlagPlace of publication
233 Spring St, New York, USA, NY, 10013Rights statement
Copyright 2011 Springer-VerlagRepository Status
- Restricted