Mild hydrolysis of chemically stable valerolactams by a biocatalytic ATP-dependent system fueled by metaphosphate.

Autor:	Roth S; Institute of Chemistry, University of Graz Heinrichstrasse 28 8010 Graz Austria melanie.hall@uni-graz.at., Gandomkar S; Institute of Chemistry, University of Graz Heinrichstrasse 28 8010 Graz Austria melanie.hall@uni-graz.at., Rossi F; Institute of Chemistry, University of Graz Heinrichstrasse 28 8010 Graz Austria melanie.hall@uni-graz.at., Hall M; Institute of Chemistry, University of Graz Heinrichstrasse 28 8010 Graz Austria melanie.hall@uni-graz.at.; BioHealth, University of Graz Heinrichstrasse 28 8010 Graz Austria.
Jazyk:	angličtina
Zdroj:	Green chemistry : an international journal and green chemistry resource : GC [Green Chem] 2023 Dec 07; Vol. 26 (8), pp. 4498-4505. Date of Electronic Publication: 2023 Dec 07 (Print Publication: 2024).
DOI:	10.1039/d3gc04434c
Abstrakt:	Medium-sized 5- and 6-membered ring lactams are molecules with remarkable stability, in contrast to smaller β-lactams. As monomers, they grant access to nylon-4 and nylon-5, which are alternative polyamides to widespread caprolactam-based nylon-6. Chemical hydrolysis of monocyclic γ- and δ-lactams to the corresponding amino acids requires harsh reaction conditions and up to now, no mild (enzymatic) protocol has been reported. Herein, the biocatalytic potential of a pair of heterologously expressed bacterial ATP-dependent oxoprolinases - OplA and OplB - was exploited. Strong activity in the presence of excess of ATP was monitored on δ-valerolactam and derivatives thereof, while trace activity was detected on γ-butyrolactam. An ATP recycling system based on cheap Graham's salt (sodium metaphosphate) and a polyphosphate kinase allowed the use of catalytic amounts of ATP, leading to up to full conversion of 10 mM δ-valerolactam at 30 °C in aqueous medium. Further improvements were obtained by co-expressing OplA and OplB using the pETDuet1 vector, a strategy which enhanced the soluble expression yield and the protein stability. Finally, a range of phosphodonors was investigated in place of ATP. With acetyl phosphate and carbamoyl phosphate, turnover numbers up to 176 were reached, providing hints on a possible mechanism, which was studied by 31 P-NMR. Competing Interests: The authors declare that there are no conflicts of interest. (This journal is © The Royal Society of Chemistry.)
Databáze:	MEDLINE
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