1uv4
From Proteopedia
Native Bacillus subtilis Arabinanase Arb43A
Structural highlights
Function[EABN1_BACSU] Involved in the degradation of arabinan and is a key enzyme in the complete degradation of the plant cell wall. Catalyzes the internal cleavage of alpha-(1->5)-L-arabinofuranosyl residues of linear 1,5-alpha-L-arabinan and of branched sugar beet arabinan. It displays no activity against heavily substituted arabinans or a range of other polysaccharides (larch wood arabinogalactan, wheat arabinoxylan and p-nitrophenyl-alpha-L-arabinofuranoside). The enzyme activity is progressively reduced as alpha-(1->5)-chains become shorter or more highly substituted.[1] [2] [3] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedEnzymes acting on polymeric substrates are frequently classified as exo or endo, reflecting their preference for, or ignorance of, polymer chain ends. Most biotechnological applications, especially in the field of polysaccharide degradation, require either endo- or exo-acting hydrolases, or they harness the essential synergy between these two modes of action. Here, we have used genomic data in tandem with structure to modify, radically, the chain-end specificity of the Cellvibrio japonicus exo-arabinanase CjArb43A. The structure of Bacillus subtilis endo-arabinanase 43A (BsArb43A) in harness with chain-end recognition kinetics of CjArb43A directed a rational design approach that led to the conversion of the Cellvibrio enzyme from an exo to an endo mode of action. One of the exo-acting mutants, D35L/Q316A, displays similar activity to WT CjArb43A and the removal of the steric block mediated by the side chains of Gln-316 and Asp-53 at the -3 subsite confers its capacity to attack internal glycoside bonds. This study provides a template for the production of tailored industrial catalysts. The introduction of subtle changes informed by comparative 3D structural and genomic data can lead to fundamental changes in the mode of action of these enzymes. Tailored catalysts for plant cell-wall degradation: redesigning the exo/endo preference of Cellvibrio japonicus arabinanase 43A.,Proctor MR, Taylor EJ, Nurizzo D, Turkenburg JP, Lloyd RM, Vardakou M, Davies GJ, Gilbert HJ Proc Natl Acad Sci U S A. 2005 Feb 22;102(8):2697-702. Epub 2005 Feb 11. PMID:15708971[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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