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Title: Structural studies of Neurospora crassa LPMO9D and redox partner CDHIIA using neutron crystallography and small-angle scattering

Sensitivity to hydrogen/deuterium and lack of observable radiation damage makes cold neutrons an ideal probe the structural studies of proteins with highly photosensitive groups such as the copper center of lytic polysaccharide monooxygenases (LPMOs) and flavin adenine dinucleotide (FAD) and heme redox cofactors of cellobiose dehydrogenases (CDHs). In this paper, neutron crystallography and small-angle neutron scattering are used to investigate Neurospora crassa LPMO9D (NcLPMO9D) and CDHIIA (NcCDHIIA), respectively. The presence of LPMO greatly enhances the efficiency of commercial glycoside hydrolase cocktails in the depolymerization of cellulose. LPMOs can receive electrons from CDHs to activate molecular dioxygen for the oxidation of cellulose resulting in chain cleavage and disruption of local crystallinity. Using neutron protein crystallography, the hydrogen/deuterium atoms of NcLPMO9D could be located throughout the structure. At the copper active site, the protonation states of the side chains of His1, His84, His157 and Tyr168, and the orientation of water molecules could be determined. Small-angle neutron scattering measurements provided low resolution models of NcCDHIIA with both the dehydrogenase and cytochrome domains in oxidized states that exhibited elongated conformations. Finally, this work demonstrates the suitability of neutron diffraction and scattering for characterizing enzymes critical to oxidative cellulose deconstruction.
 [1] ; ORCiD logo [1] ;  [2] ;  [1]
  1. North Carolina State Univ., Raleigh, NC (United States). Dept. of Molecular and Structural Biochemistry; Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Neutron Sciences Directorate
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Neutron Sciences Directorate
Publication Date:
Grant/Contract Number:
AC05-00OR22725; MRI 09229719; IGERT1069091; 1010523
Accepted Manuscript
Journal Name:
Carbohydrate Research
Additional Journal Information:
Journal Volume: 448; Journal ID: ISSN 0008-6215
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); North Carolina State Univ., Raleigh, NC (United States)
Sponsoring Org:
USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23); USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); National Science Foundation (NSF); USDA National Inst. of Food and Agriculture (NIFA)
Country of Publication:
United States
59 BASIC BIOLOGICAL SCIENCES; polysaccharide monooxygenases; cellobiose dehydrogenases; neutron diffraction; neutron scattering; x-ray induced photoreduction
OSTI Identifier: