6fw2
Crystal Structure of human mARC1
Structural highlights
FunctionENLYS_BPT4 Endolysin with lysozyme activity that degrades host peptidoglycans and participates with the holin and spanin proteins in the sequential events which lead to the programmed host cell lysis releasing the mature viral particles. Once the holin has permeabilized the host cell membrane, the endolysin can reach the periplasm and break down the peptidoglycan layer.[1] MARC1_HUMAN As a component of an N-hydroxylated prodrug-converting complex required to reduce N-hydroxylated prodrugs, such as benzamidoxime. Also able to reduce N(omega)-hydroxy-L-arginine (NOHA) and N(omega)-hydroxy-N(delta)-methyl-L-arginine (NHAM) into L-arginine and N(delta)-methyl-L-arginine, respectively.[2] Publication Abstract from PubMedBiotransformation enzymes ensure a viable homeostasis by regulating reversible cycles of oxidative and reductive reactions. The metabolism of nitrogen-containing compounds is of high pharmaceutical and toxicological relevance because N-oxygenated metabolites derived from reactions mediated by cytochrome P450 enzymes or flavin-dependent monooxygenases are in some cases highly toxic or mutagenic. The molybdenum-dependent mitochondrial amidoxime-reducing component (mARC) was found to be an extremely efficient counterpart, which is able to reduce the full range of N-oxygenated compounds and thereby mediates detoxification reactions. However, the 3D structure of this enzyme was unknown. Here we present the high-resolution crystal structure of human mARC. We give detailed insight into the coordination of its molybdenum cofactor (Moco), the catalytic mechanism, and its ability to reduce a wide range of N-oxygenated compounds. The identification of two key residues will allow future discrimination between mARC paralogs and ensure correct annotation. Since our structural findings contradict in silico predictions that are currently made by online databases, we propose domain definitions for members of the superfamily of Moco sulfurase C-terminal (MOSC) domain-containing proteins. Furthermore, we present evidence for an evolutionary role of mARC for the emergence of the xanthine oxidase protein superfamily. We anticipate the hereby presented crystal structure to be a starting point for future descriptions of MOSC proteins, which are currently poorly structurally characterized. Crystal structure of human mARC1 reveals its exceptional position among eukaryotic molybdenum enzymes.,Kubitza C, Bittner F, Ginsel C, Havemeyer A, Clement B, Scheidig AJ Proc Natl Acad Sci U S A. 2018 Nov 5. pii: 1808576115. doi:, 10.1073/pnas.1808576115. PMID:30397129[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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