TY - JOUR
T1 - Insights into an unusual Auxiliary Activity 9 family member lacking the histidine brace motif of lytic polysaccharide monooxygenases
AU - Frandsen, Kristian E H
AU - Tovborg, Morten
AU - Jørgensen, Christian I.
AU - Spodsberg, Nikolai
AU - Rosso, Marie-Noëlle
AU - Hemsworth, Glyn R
AU - Garman, Elspeth F
AU - Grime, Geoffrey W
AU - Poulsen, Jens-Christian N
AU - Batth, Tanveer S.
AU - Miyauchi, Shingo
AU - Lipzen, Anna
AU - Daum, Chris
AU - Grigoriev, Igor V
AU - Johansen, Katja S
AU - Henrissat, Bernard
AU - Berrin, Jean-Guy
AU - Lo Leggio, Leila
N1 - Published under license by The American Society for Biochemistry and Molecular Biology, Inc.
PY - 2019/11/8
Y1 - 2019/11/8
N2 - Lytic polysaccharide monooxygenases (LPMOs) are redoxenzymes involved in biomass degradation. All characterized LPMOs possess an active site of two highly conserved histidine residues coordinating a copper ion (the histidine brace), which are essential for LPMO activity. However, some protein sequences that belong to the AA9 LPMO family display a natural N-terminal His to Arg substitution (Arg-AA9). These are found almost entirely in the phylogenetic fungal class Agaricomycetes, associated with wood decay, but no function has been demonstrated for any Arg-AA9. Through bioinformatics, transcriptomic, and proteomic analyses we present data, which suggest that Arg-AA9 proteins could have a hitherto unidentified role in fungal degradation of lignocellulosic biomass in conjunction with other secreted fungal enzymes. We present the first structure of an ArgAA9, LsAA9B, a naturally occurring protein from Lentinus similis. The LsAA9B structure reveals gross changes in the region equivalent to the canonical LPMO copper-binding site, whereas features implicated in carbohydrate binding in AA9 LPMOs have been maintained. We obtained a structure of LsAA9B with xylotetraose bound on the surface of the protein although with a considerably different binding mode compared with other AA9 complex structures. In addition, we have found indications of protein phosphorylationneartheN-terminalArg andthe carbohydrate-binding site, for which the potential function is currently unknown. Our results are strong evidence that Arg-AA9s function markedly different from canonical AA9 LPMO, but nonetheless, may play a role in fungal conversion of lignocellulosic biomass.
AB - Lytic polysaccharide monooxygenases (LPMOs) are redoxenzymes involved in biomass degradation. All characterized LPMOs possess an active site of two highly conserved histidine residues coordinating a copper ion (the histidine brace), which are essential for LPMO activity. However, some protein sequences that belong to the AA9 LPMO family display a natural N-terminal His to Arg substitution (Arg-AA9). These are found almost entirely in the phylogenetic fungal class Agaricomycetes, associated with wood decay, but no function has been demonstrated for any Arg-AA9. Through bioinformatics, transcriptomic, and proteomic analyses we present data, which suggest that Arg-AA9 proteins could have a hitherto unidentified role in fungal degradation of lignocellulosic biomass in conjunction with other secreted fungal enzymes. We present the first structure of an ArgAA9, LsAA9B, a naturally occurring protein from Lentinus similis. The LsAA9B structure reveals gross changes in the region equivalent to the canonical LPMO copper-binding site, whereas features implicated in carbohydrate binding in AA9 LPMOs have been maintained. We obtained a structure of LsAA9B with xylotetraose bound on the surface of the protein although with a considerably different binding mode compared with other AA9 complex structures. In addition, we have found indications of protein phosphorylationneartheN-terminalArg andthe carbohydrate-binding site, for which the potential function is currently unknown. Our results are strong evidence that Arg-AA9s function markedly different from canonical AA9 LPMO, but nonetheless, may play a role in fungal conversion of lignocellulosic biomass.
U2 - 10.1074/jbc.ra119.009223
DO - 10.1074/jbc.ra119.009223
M3 - Journal article
C2 - 31471321
SN - 0021-9258
VL - 294
SP - 17117
EP - 17130
JO - The Journal of Biological Chemistry
JF - The Journal of Biological Chemistry
ER -