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Exploring Multimodularity in Plant Cell Wall Deconstruction: STRUCTURAL AND FUNCTIONAL ANALYSIS OF Xyn10C CONTAINING THE CBM22-1-CBM22-2 TANDEM.
- Source :
-
The Journal of biological chemistry [J Biol Chem] 2015 Jul 10; Vol. 290 (28), pp. 17116-30. Date of Electronic Publication: 2015 May 22. - Publication Year :
- 2015
-
Abstract
- Elucidating the molecular mechanisms regulating multimodularity is a challenging task. Paenibacillus barcinonensis Xyn10C is a 120-kDa modular enzyme that presents the CBM22/GH10/CBM9 architecture found in a subset of large xylanases. We report here the three-dimensional structure of the Xyn10C N-terminal region, containing the xylan-binding CBM22-1-CBM22-2 tandem (Xyn10C-XBD), which represents the first solved crystal structure of two contiguous CBM22 modules. Xyn10C-XBD is folded into two separate CBM22 modules linked by a flexible segment that endows the tandem with extraordinary plasticity. Each isolated domain has been expressed and crystallized, and their binding abilities have been investigated. Both domains contain the R(W/Y)YYE motif required for xylan binding. However, crystallographic analysis of CBM22-2 complexes shows Trp-308 as an additional binding determinant. The long loop containing Trp-308 creates a platform that possibly contributes to the recognition of precise decorations at subsite S2. CBM22-2 may thus define a subset of xylan-binding CBM22 modules directed to particular regions of the polysaccharide. Affinity electrophoresis reveals that Xyn10C-XBD binds arabinoxylans more tightly, which is more apparent when CBM22-2 is tested against highly substituted xylan. The crystal structure of the catalytic domain, also reported, shows the capacity of the active site to accommodate xylan substitutions at almost all subsites. The structural differences found at both Xyn10C-XBD domains are consistent with the isothermal titration calorimetry experiments showing two sites with different affinities in the tandem. On the basis of the distinct characteristics of CBM22, a delivery strategy of Xyn10C mediated by Xyn10C-XBD is proposed.<br /> (© 2015 by The American Society for Biochemistry and Molecular Biology, Inc.)
- Subjects :
- Amino Acid Sequence
Bacterial Proteins genetics
Base Sequence
Catalytic Domain
Crystallography, X-Ray
DNA, Bacterial genetics
Endo-1,4-beta Xylanases genetics
Ligands
Models, Molecular
Molecular Sequence Data
Paenibacillus genetics
Protein Conformation
Protein Interaction Domains and Motifs
Protein Structure, Quaternary
Recombinant Proteins chemistry
Recombinant Proteins genetics
Recombinant Proteins metabolism
Xylans metabolism
Bacterial Proteins chemistry
Bacterial Proteins metabolism
Cell Wall metabolism
Endo-1,4-beta Xylanases chemistry
Endo-1,4-beta Xylanases metabolism
Paenibacillus enzymology
Plants metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 1083-351X
- Volume :
- 290
- Issue :
- 28
- Database :
- MEDLINE
- Journal :
- The Journal of biological chemistry
- Publication Type :
- Academic Journal
- Accession number :
- 26001782
- Full Text :
- https://doi.org/10.1074/jbc.M115.659300