9za6
Neurospora crassa polysaccharide monooxygenase 9D dose series - pseudohelix 23 (5.51 MGy)
Structural highlights
FunctionLPMO_NEUCR Catalyzes the oxidative cleavage of glycosidic bonds in cellulosic substrates via a copper-dependent mechanism (PubMed:22004347, PubMed:22188218, PubMed:24350607, PubMed:31431506). In the presence of an exogenous reductant ascorbic acid, degrades phosphoric acid swollen cellulose (PASC) to cello-oligosaccharides and 4-ketoaldoses, the end products oxidized at the non-reducing end (PubMed:22004347, PubMed:22188218, PubMed:24350607). Somewhat active toward tamarind xyloglucan and konjac glucomannan, with improved activity with glucomannan in the presence of PASC (PubMed:31431506). H(2)O(2) is able to substitute for O(2) in reactions with PASC, xyloglucan and glucomannan (PubMed:31431506). Very weak activity on cellopentaose (PubMed:31431506). No activity with birchwood xylan or ivory nut mannan (PubMed:31431506). Disrupts plant cell wall polysaccharide substrates, such as recalcitrant crystalline cellulose (Probable).[1] [2] [3] [4] Publication Abstract from PubMedStructural studies of copper-containing lytic polysaccharide monooxygenases (LPMOs) by X-ray crystallography are often complicated by radiation damage. In this study, we analyze a series of 36 X-ray crystal structures of NcAA9D, a Neurospora crassa AA9-family LPMO, determined from data collected at cryogenic temperature from a single crystal to investigate the progressive effects of radiation damage at the active site of this enzyme. We report new insights into the dose-dependence of active-site geometry in LPMOs and utilize the unique pre-bound dioxygen site of NcAA9D to analyze the impact of X-ray dose on the electron density of this species. It is well established that photoreduction of the LPMO active-site copper(II) leads to expulsion of its water ligands. We further characterize this displacement and the corresponding electron-density smearing, a phenomenon that can lead to the erroneous modeling of copper-bound dioxygen species. These findings suggest that radiation-dose series collected from a single crystal provide invaluable data to support unambiguous assignment of radiation-sensitive intermediates at the active site of LPMOs and other radiation-sensitive redox enzymes. Dose-dependent structural and electron-density features in the lytic polysaccharide monooxygenase NcAA9D.,Miller SA, O'Dell WB, Meilleur F Acta Crystallogr D Struct Biol. 2026 Aug 1;82(Pt 8):900-914. doi: , 10.1107/S205979832600639X. Epub 2026 Jul 28. PMID:42517195[5] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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