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PDBsum entry 4hap
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References listed in PDB file
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Key reference
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Title
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Structural characterization of a unique marine animal family 7 cellobiohydrolase suggests a mechanism of cellulase salt tolerance.
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Authors
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M.Kern,
J.E.Mcgeehan,
S.D.Streeter,
R.N.Martin,
K.Besser,
L.Elias,
W.Eborall,
G.P.Malyon,
C.M.Payne,
M.E.Himmel,
K.Schnorr,
G.T.Beckham,
S.M.Cragg,
N.C.Bruce,
S.J.Mcqueen-Mason.
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Ref.
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Proc Natl Acad Sci U S A, 2013,
110,
10189-10194.
[DOI no: ]
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PubMed id
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Abstract
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Nature uses a diversity of glycoside hydrolase (GH) enzymes to convert
polysaccharides to sugars. As lignocellulosic biomass deconstruction for biofuel
production remains costly, natural GH diversity offers a starting point for
developing industrial enzymes, and fungal GH family 7 (GH7) cellobiohydrolases,
in particular, provide significant hydrolytic potential in industrial mixtures.
Recently, GH7 enzymes have been found in other kingdoms of life besides fungi,
including in animals and protists. Here, we describe the in vivo spatial
expression distribution, properties, and structure of a unique endogenous GH7
cellulase from an animal, the marine wood borer Limnoria quadripunctata
(LqCel7B). RT-quantitative PCR and Western blot studies show that LqCel7B is
expressed in the hepatopancreas and secreted into the gut for wood degradation.
We produced recombinant LqCel7B, with which we demonstrate that LqCel7B is a
cellobiohydrolase and obtained four high-resolution crystal structures. Based on
a crystallographic and computational comparison of LqCel7B to the
well-characterized Hypocrea jecorina GH7 cellobiohydrolase, LqCel7B exhibits an
extended substrate-binding motif at the tunnel entrance, which may aid in
substrate acquisition and processivity. Interestingly, LqCel7B exhibits striking
surface charges relative to fungal GH7 enzymes, which likely results from
evolution in marine environments. We demonstrate that LqCel7B stability and
activity remain unchanged, or increase at high salt concentration, and that the
L. quadripunctata GH mixture generally contains cellulolytic enzymes with highly
acidic surface charge compared with enzymes derived from terrestrial microbes.
Overall, this study suggests that marine cellulases offer significant potential
for utilization in high-solids industrial biomass conversion processes.
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Secondary reference #1
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Title
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Molecular insight into lignocellulose digestion by a marine isopod in the absence of gut microbes.
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Authors
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A.J.King,
S.M.Cragg,
Y.Li,
J.Dymond,
M.J.Guille,
D.J.Bowles,
N.C.Bruce,
I.A.Graham,
S.J.Mcqueen-Mason.
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Ref.
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Proc Natl Acad Sci U S A, 2010,
107,
5345-5350.
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PubMed id
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