Mapping the DNA-Binding Motif of Scabin Toxin, a Guanine Modifying Enzyme from Streptomyces scabies
1
Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON N1G 2W1, Canada
2
Department of Biochemistry and Molecular Biology and Center for Blood Research, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
3
Department of Biochemistry, McGill University, Montreal, QC H3G 1Y6, Canada
4
Department of Biological Sciences, Brock University, St. Catherines, ON L2S 3A1, Canada
*
Author to whom correspondence should be addressed.
†
These authors contributed equally to this work.
Toxins 2021, 13(1), 55; https://doi.org/10.3390/toxins13010055
Received: 12 November 2020 / Revised: 23 December 2020 / Accepted: 9 January 2021 / Published: 13 January 2021
(This article belongs to the Special Issue Structure and Function of Bacterial ADP-Ribosylation Toxins)
Scabin is a mono-ADP-ribosyltransferase toxin/enzyme and possible virulence factor produced by the agriculture pathogen, Streptomyces scabies. Recently, molecular dynamic approaches and MD simulations revealed its interaction with both NAD+ and DNA substrates. An Essential Dynamics Analysis identified a crab-claw-like mechanism, including coupled changes in the exposed motifs, and the Rβ1-RLa-NLc-STTβ2-WPN-WARTT-(QxE)ARTT sequence motif was proposed as a catalytic signature of the Pierisin family of DNA-acting toxins. A new fluorescence assay was devised to measure the kinetics for both RNA and DNA substrates. Several protein variants were prepared to probe the Scabin-NAD-DNA molecular model and to reveal the reaction mechanism for the transfer of ADP-ribose to the guanine base in the DNA substrate. The results revealed that there are several lysine and arginine residues in Scabin that are important for binding the DNA substrate; also, key residues such as Asn110 in the mechanism of ADP-ribose transfer to the guanine base were identified. The DNA-binding residues are shared with ScARP from Streptomyces coelicolor but are not conserved with Pierisin-1, suggesting that the modification of guanine bases by ADP-ribosyltransferases is divergent even in the Pierisin family.
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Keywords:
bacterial toxins; crystallography; enzyme kinetics; DNA-binding motif; bioinformatics; DNA modification; molecular modeling
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MDPI and ACS Style
Vatta, M.; Lyons, B.; Heney, K.A.; Lidster, T.; Merrill, A.R. Mapping the DNA-Binding Motif of Scabin Toxin, a Guanine Modifying Enzyme from Streptomyces scabies. Toxins 2021, 13, 55. https://doi.org/10.3390/toxins13010055
AMA Style
Vatta M, Lyons B, Heney KA, Lidster T, Merrill AR. Mapping the DNA-Binding Motif of Scabin Toxin, a Guanine Modifying Enzyme from Streptomyces scabies. Toxins. 2021; 13(1):55. https://doi.org/10.3390/toxins13010055
Chicago/Turabian StyleVatta, Maritza; Lyons, Bronwyn; Heney, Kayla A.; Lidster, Taylor; Merrill, A. R. 2021. "Mapping the DNA-Binding Motif of Scabin Toxin, a Guanine Modifying Enzyme from Streptomyces scabies" Toxins 13, no. 1: 55. https://doi.org/10.3390/toxins13010055
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