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ACS Catal

Title:		A Cold-Active Flavin-Dependent Monooxygenase from Janthinobacterium svalbardensis Unlocks Applications of Baeyer-Villiger Monooxygenases at Low Temperature
Author(s):		Chanique AM; Polidori N; Sovic L; Kracher D; Assil-Companioni L; Galuska P; Parra LP; Gruber K; Kourist R;
Address:		"NAWI Graz, BioTechMed-Graz, Institute of Molecular Biotechnology, Graz University of Technology, Petersgasse 14, Graz 8010, Austria. Department of Chemical and Bioprocesses Engineering, School of Engineering, Pontificia Universidad Catolica de Chile, Vicuna Mackenna 4860, Santiago 7810000, Chile. NAWI Graz, BioTechMed Graz, Institute of Molecular Biosciences, University of Graz, Humboldtstrasse 50, Graz 8010, Austria. ACIB GmbH, Petersgasse 14/1, Graz 8010, Austria. Schools of Engineering, Medicine and Biological Sciences, Institute for Biological and Medical Engineering, Pontificia Universidad Catolica de Chile, Vicuna Mackenna 4860, Santiago 7810000, Chile"
Journal Title:		ACS Catal
Year:		2023
Volume:		20230227
Issue:		6
Page Number:		3549 - 3562
DOI:		10.1021/acscatal.2c05160
ISSN/ISBN:		2155-5435 (Print) 2155-5435 (Electronic)
Abstract:		"Cold-active enzymes maintain a large part of their optimal activity at low temperatures. Therefore, they can be used to avoid side reactions and preserve heat-sensitive compounds. Baeyer-Villiger monooxygenases (BVMO) utilize molecular oxygen as a co-substrate to catalyze reactions widely employed for steroid, agrochemical, antibiotic, and pheromone production. Oxygen has been described as the rate-limiting factor for some BVMO applications, thereby hindering their efficient utilization. Considering that oxygen solubility in water increases by 40% when the temperature is decreased from 30 to 10 degrees C, we set out to identify and characterize a cold-active BVMO. Using genome mining in the Antarctic organism Janthinobacterium svalbardensis, a cold-active type II flavin-dependent monooxygenase (FMO) was discovered. The enzyme shows promiscuity toward NADH and NADPH and high activity between 5 and 25 degrees C. The enzyme catalyzes the monooxygenation and sulfoxidation of a wide range of ketones and thioesters. The high enantioselectivity in the oxidation of norcamphor (eeS = 56%, eeP > 99%, E > 200) demonstrates that the generally higher flexibility observed in the active sites of cold-active enzymes, which compensates for the lower motion at cold temperatures, does not necessarily reduce the selectivity of these enzymes. To gain a better understanding of the unique mechanistic features of type II FMOs, we determined the structure of the dimeric enzyme at 2.5 A resolution. While the unusual N-terminal domain has been related to the catalytic properties of type II FMOs, the structure shows a SnoaL-like N-terminal domain that is not interacting directly with the active site. The active site of the enzyme is accessible only through a tunnel, with Tyr-458, Asp-217, and His-216 as catalytic residues, a combination not observed before in FMOs and BVMOs"
Keywords:
Notes:		"PubMed-not-MEDLINEChanique, Andrea M Polidori, Nakia Sovic, Lucija Kracher, Daniel Assil-Companioni, Leen Galuska, Philipp Parra, Loreto P Gruber, Karl Kourist, Robert eng 2023/03/28 ACS Catal. 2023 Feb 27; 13(6):3549-3562. doi: 10.1021/acscatal.2c05160. eCollection 2023 Mar 17"