 |
PDBsum entry 5o2w
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Oxidoreductase
|
PDB id
|
|
|
|
5o2w
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
References listed in PDB file
|
|
|
Key reference
|
|
|
Title
|
|
High-Resolution structure of a lytic polysaccharide monooxygenase fromhypocrea jecorinareveals a predicted linker as an integral part of the catalytic domain.
|
|
|
Authors
|
|
H.Hansson,
S.Karkehabadi,
N.Mikkelsen,
N.R.Douglas,
S.Kim,
A.Lam,
T.Kaper,
B.Kelemen,
K.K.Meier,
S.M.Jones,
E.I.Solomon,
M.Sandgren.
|
|
|
Ref.
|
|
J Biol Chem, 2017,
292,
19099-19109.
|
|
|
PubMed id
|
|
|
|
|
|
Abstract
|
|
|
For decades, the enzymes of the fungusHypocrea jecorinahave served as a
model system for the breakdown of cellulose. Three-dimensional structures for
almost allH. jecorinacellulose-degrading enzymes are available, except
forHjLPMO9A, belonging to the AA9 family of lytic polysaccharide
monooxygenases (LPMOs). These enzymes enhance the hydrolytic activity of
cellulases and are essential for cost-efficient conversion of lignocellulosic
biomass. Here, using structural and spectroscopic analyses, we found that
nativeHjLPMO9A contains a catalytic domain and a family-1
carbohydrate-binding module (CBM1) connected via a linker sequence. A C
terminally truncated variant ofHjLPMO9A containing 21 residues of the
predicted linker was expressed at levels sufficient for analysis. Here, using
structural, spectroscopic, and biochemical analyses, we found that this
truncated variant exhibited reduced binding to and activity on cellulose
compared with the full-length enzyme. Importantly, a 0.95-Å resolution X-ray
structure of truncatedHjLPMO9A revealed that the linker forms an integral
part of the catalytic domain structure, covering a hydrophobic patch on the
catalytic AA9 module. We noted that the oxidized catalytic center contains a
Cu(II) coordinated by two His ligands, one of which has a His-brace in which the
His-1 terminal amine group also coordinates to a copper. The final equatorial
position of the Cu(II) is occupied by a water-derived ligand. The spectroscopic
characteristics of the truncated variant were not measurably different from
those of full-lengthHjLPMO9A, indicating that the presence of the CBM1
module increases the affinity ofHjLPMO9A for cellulose binding, but does
not affect the active site.
|
|
|
|
|
|
|
