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Structural basis of the properties of an industrially relevant thermophilic xylanase
Author(s) -
Harris Gillian W.,
Pickersgill Richard W.,
Connerton Ian,
Debeire Philippe,
Touzel JeanPierre,
Breton Christelle,
Pérez Serge
Publication year - 1997
Publication title -
proteins: structure, function, and bioinformatics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.699
H-Index - 191
eISSN - 1097-0134
pISSN - 0887-3585
DOI - 10.1002/(sici)1097-0134(199709)29:1<77::aid-prot6>3.0.co;2-c
Subject(s) - xylanase , thermostability , thermophile , chemistry , enzyme , bleach , polymer , ethylene glycol , chemical engineering , biochemistry , organic chemistry , engineering
A thermophilic xylanase from Bacillus strain D3 suitable for use as a bleach booster in the paper pulping industry has been identified and characterized. The enzyme is suited to the high temperature and alkaline conditions needed for using xylanases in the pulp industry. The xylanase is stable at 60°C and relatively stable at high temperatures, with a temperature optimum of 75°C. The pH optimum is 6, but the enzyme is active over a broad pH range. The xylanase has been cloned and sequenced, and the crystal structure has been determined. The structure of Bacillus D3 xylanase reveals an unusual feature of surface aromatic residues, which form clusters or “sticky patches” between pairs of molecules. These “sticky patches” on the surface of the enzyme are responsible for the tendency of the protein to aggregate at high concentrations in the absence of reagents such as ethylene glycol. The formation of dimers and higher order polymers via these hydrophobic contacts may also contribute to the thermostability of this xylanase. Proteins 29:77–86, 1997. © 1997 Wiley‐Liss, Inc.