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232 a.a.
Key reference
DOI no: 10.1074/jbc.M700224200 J Biol Chem 282:19177-19189 (2007) PubMed id: 17376777
Characterization and three-dimensional structures of two distinct bacterial xyloglucanases from families GH5 and GH12. T.M.Gloster, F.M.Ibatullin, K.Macauley, J.M.Eklöf, S.Roberts, J.P.Turkenburg, M.E.Bjørnvad, P.L.Jørgensen, S.Danielsen, K.S.Johansen, T.V.Borchert, K.S.Wilson, H.Brumer, G.J.Davies. ABSTRACT
The plant cell wall is a complex material in which the cellulose microfibrils are embedded within a mesh of other polysaccharides, some of which are loosely termed "hemicellulose." One such hemicellulose is xyloglucan, which displays a beta-1,4-linked d-glucose backbone substituted with xylose, galactose, and occasionally fucose moieties. Both xyloglucan and the enzymes responsible for its modification and degradation are finding increasing prominence, reflecting both the drive for enzymatic biomass conversion, their role in detergent applications, and the utility of modified xyloglucans for cellulose fiber modification. Here we present the enzymatic characterization and three-dimensional structures in ligand-free and xyloglucan-oligosaccharide complexed forms of two distinct xyloglucanases from glycoside hydrolase families GH5 and GH12. The enzymes, Paenibacillus pabuli XG5 and Bacillus licheniformis XG12, both display open active center grooves grafted upon their respective (beta/alpha)(8) and beta-jelly roll folds, in which the side chain decorations of xyloglucan may be accommodated. For the beta-jelly roll enzyme topology of GH12, binding of xylosyl and pendant galactosyl moieties is tolerated, but the enzyme is similarly competent in the degradation of unbranched glucans. In the case of the (beta/alpha)(8) GH5 enzyme, kinetically productive interactions are made with both xylose and galactose substituents, as reflected in both a high specific activity on xyloglucan and the kinetics of a series of aryl glycosides. The differential strategies for the accommodation of the side chains of xyloglucan presumably facilitate the action of these microbial hydrolases in milieus where diverse and differently substituted substrates may be encountered.
Selected figure(s)
Figure 6.
FIGURE 6. Schematic diagram of the interactions of PpXG5 with XXLG.Figure 10.
FIGURE 10. Schematic diagram of the interactions of BlXG12 with XXXG/XX.The above figures are reprinted by permission from the ASBMB: J Biol Chem (2007, 282, 19177-19189) copyright 2007. Figures were selected by an automated process.
Literature references that cite this PDB file's key reference
PubMed id Reference
18658283 T.Shimokawa, H.Shibuya, M.Nojiri, S.Yoshida, and M.Ishihara (2008).
Purification, molecular cloning, and enzymatic properties of a family 12 endoglucanase (EG-II) from fomitopsis palustris: role of EG-II in larch holocellulose hydrolysis.Appl Environ Microbiol, 74, 5857-5861.
18043802 K.Piens, A.M.Henriksson, F.Gullfot, M.Lopez, R.Fauré, F.M.Ibatullin, T.T.Teeri, H.Driguez, and H.Brumer (2007).
Glycosynthase activity of hybrid aspen xyloglucan endo-transglycosylase PttXET16-34 nucleophile mutants.Org Biomol Chem, 5, 3971-3978. The most recent references are shown first. Citation data come partly from CiteXplore and partly from an automated harvesting procedure. Note that this is likely to be only a partial list as not all journals are covered by either method. However, we are continually building up the citation data so more and more references will be included with time.
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