TY - JOUR
T1 - Multidomain, surface layer-associated glycoside hydrolases contribute to plant polysaccharide degradation by caldicellulosiruptor species
AU - Conway, Jonathan M.
AU - Pierce, William S.
AU - Le, Jaycee H.
AU - Harper, George W.
AU - Wright, John H.
AU - Tucker, Allyson L.
AU - Zurawski, Jeffrey V.
AU - Lee, Laura L.
AU - Blumer-Schuette, Sara E.
AU - Kelly, Robert M.
N1 - Publisher Copyright:
©2016 by The American Society for Biochemistry and Molecular Biology, Inc.
PY - 2016/3/25
Y1 - 2016/3/25
N2 - The genome of the extremely thermophilic bacterium Caldicellulosiruptor kronotskyensis encodes 19 surface layer (S-layer) homology (SLH) domain-containing proteins, the most in any Caldicellulosiruptor species genome sequenced to date. These SLH proteins include five glycoside hydrolases (GHs) and one polysaccharide lyase, the genes for which were transcribed at high levels during growth on plant biomass. The largest GH identified so far in this genus, Calkroβ0111 (2,435 amino acids), is completely unique to C. kronotskyensis and contains SLH domains. Calkro-0111 was produced recombinantly in Escherichia coli as two pieces, containing the GH16 and GH55 domains, respectively, as well as putative binding and spacer domains. These displayed endo- And exoglucanase activity on theβ-1,3-1,6-glucan laminarin. A series of additional truncation mutants of Calkro-0111 revealed the essential architectural features required for catalytic function. Calkro-0402, another of the SLH domain GHs in C. kronotskyensis, when produced in E. coli, was active on a variety of xylans and β-glucans. Unlike Calkro-0111, Calkro-0402 is highly conserved in the genus Caldicellulosiruptor and among other biomass-degrading Firmicutes but missing from Caldicellulosiruptor bescii. As such, the gene encoding Calkro-0402 was inserted into the C. bescii genome, creating a mutant strain with its S-layer extensively decorated with Calkro-0402. This strain consequently degraded xylans more extensively than wild-type C. bescii. The results here provide new insights into the architecture and role of SLH domain GHs and demonstrate that hemicellulose degradation can be enhanced through non-native SLH domain GHs engineered into the genomes of Caldicellulosiruptor species.
AB - The genome of the extremely thermophilic bacterium Caldicellulosiruptor kronotskyensis encodes 19 surface layer (S-layer) homology (SLH) domain-containing proteins, the most in any Caldicellulosiruptor species genome sequenced to date. These SLH proteins include five glycoside hydrolases (GHs) and one polysaccharide lyase, the genes for which were transcribed at high levels during growth on plant biomass. The largest GH identified so far in this genus, Calkroβ0111 (2,435 amino acids), is completely unique to C. kronotskyensis and contains SLH domains. Calkro-0111 was produced recombinantly in Escherichia coli as two pieces, containing the GH16 and GH55 domains, respectively, as well as putative binding and spacer domains. These displayed endo- And exoglucanase activity on theβ-1,3-1,6-glucan laminarin. A series of additional truncation mutants of Calkro-0111 revealed the essential architectural features required for catalytic function. Calkro-0402, another of the SLH domain GHs in C. kronotskyensis, when produced in E. coli, was active on a variety of xylans and β-glucans. Unlike Calkro-0111, Calkro-0402 is highly conserved in the genus Caldicellulosiruptor and among other biomass-degrading Firmicutes but missing from Caldicellulosiruptor bescii. As such, the gene encoding Calkro-0402 was inserted into the C. bescii genome, creating a mutant strain with its S-layer extensively decorated with Calkro-0402. This strain consequently degraded xylans more extensively than wild-type C. bescii. The results here provide new insights into the architecture and role of SLH domain GHs and demonstrate that hemicellulose degradation can be enhanced through non-native SLH domain GHs engineered into the genomes of Caldicellulosiruptor species.
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U2 - 10.1074/jbc.M115.707810
DO - 10.1074/jbc.M115.707810
M3 - Article
C2 - 26814128
AN - SCOPUS:84964853696
SN - 0021-9258
VL - 291
SP - 6732
EP - 6747
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 13
ER -