Crystal structure of endo-xylogalacturonan hydrolase from Aspergillus tubingensis
Rozeboom, H.J. ; Beldman, G. ; Schols, H.A. ; Dijkstra, B.W. - \ 2013
FEBS Journal 280 (2013)23. - ISSN 1742-464X - p. 6061 - 6069.
site-directed mutagenesis - endopolygalacturonase ii - sequence alignments - features - polysaccharides - processivity - degradation - pectin - niger - polygalacturonase
Endo-xylogalacturonan hydrolase is a member of glycoside hydrolase family 28 (GH28) that hydrolyzes the glycosidic bond between two ß-xylose-substituted galacturonic acid residues in pectin. Presented here is the X-ray crystal structure of the endo-xylogalacturonan hydrolase from Aspergillus tubingensis (XghA) at 1.75 Å resolution. The high degree of structural conservation in the active site and catalytic apparatus compared with polygalacturonases indicates that cleavage of the substrate proceeds in essentially the same way as found for the other GH28 enzymes. Molecular modeling of a xylosylated tri-galacturonate in the active site identified the amino acid residues involved in substrate binding. They border a substrate-binding cleft that is much wider than in other polygalacturonases, and can accommodate xylosylated substrates. The most extensive interactions appear to occur at subsite +2, in agreement with the enzyme kinetics results, which showed enhanced activity on substrates with a xylose attached to the galacturonic acid bound at subsite +2
Crystal Structure of Agaricus bisporus Mushroom Tyrosinase: Identity of the Tetramer Subunits and Interaction with Tropolone
Ismaya, W.T. ; Rozeboom, H.J. ; Weijn, A. ; Mes, J.J. ; Fusetti, F. ; Wichers, H.J. ; Dijkstra, B.W. - \ 2011
Biochemistry 50 (2011)24. - ISSN 0006-2960 - p. 5477 - 5486.
polyphenol oxidase - diffraction data - multiple forms - protein - mechanism - sequence - inhibition - refinement - plant - activation
Tyrosinase catalyzes the conversion of phenolic compounds into their quinone derivatives, which are precursors for the formation of melanin, a ubiquitous pigment in living organisms. Because of its importance for browning reactions in the food industry, the tyrosinase from the mushroom Agaricus bisporus has been investigated in depth. In previous studies the tyrosinase enzyme complex was shown to be a H(2)L(2) tetramer, but no clues were obtained of the identities of the subunits, their mode of association, and the 3D structure of the complex. Here we unravel this tetramer at the molecular level. Its 2.3 Å resolution crystal structure is the first structure of the full fungal tyrosinase complex. The complex comprises two H subunits of ~392 residues and two L subunits of ~150 residues. The H subunit originates from the ppo3 gene and has a fold similar to other tyrosinases, but it is ~100 residues larger. The L subunit appeared to be the product of orf239342 and has a lectin-like fold. The H subunit contains a binuclear copper-binding site in the deoxy-state, in which three histidine residues coordinate each copper ion. The side chains of these histidines have their orientation fixed by hydrogen bonds or, in the case of His85, by a thioether bridge with the side chain of Cys83. The specific tyrosinase inhibitor tropolone forms a pre-Michaelis complex with the enzyme. It binds near the binuclear copper site without directly coordinating the copper ions. The function of the ORF239342 subunits is not known. Carbohydrate binding sites identified in other lectins are not conserved in ORF239342, and the subunits are over 25 Å away from the active site, making a role in activity unlikely. The structures explain how calcium ions stabilize the tetrameric state of the enzyme
Crystallization and preliminary X-ray crystallographic analysis of tyrosinase from the mushroom Agaricus bisporus
Ismaya, W.T. ; Rozeboom, H.J. ; Schurink, M. ; Boeriu, C.G. ; Wichers, H.J. ; Dijkstra, B.W. - \ 2011
Acta Crystallographica Section F. Structural Biology and Crystallization Communications 67 (2011)5. - ISSN 1744-3091 - p. 575 - 578.
diphenolase activities - polyphenol oxidase - monophenolase - expression - mechanism
Tyrosinase catalyzes the conversion of tyrosine to dihydroxyphenylalanine quinone, which is the main precursor for the biosynthesis of melanin. The enzyme from Agaricus bisporus, the common button mushroom, was purified and crystallized in two different space groups. Crystals belonging to space group P21 (unit-cell parameters a = 104.2, b = 105.0, c = 119.1 Å, ß = 110.6°, four molecules per asymmetric unit) diffracted to 3.0 Å resolution. Crystals belonging to space group P21212 (unit-cell parameters a = 104.0, b = 104.5, c = 108.4 Å, two molecules per asymmetric unit) diffracted to 2.6 Å resolution. It was essential to include 5 mM HoCl3 in all crystallization conditions in order to obtain well diffracting crystals.
Composition of endogenous alleles can influence the level of antisense inhibition of granule-bound starch synthase gene expression in tetraploid potato plants.
Wolters, A.M.A. ; Janssen, E.M. ; Rozeboom-Schippers, M.G.M. ; Jacobsen, E. ; Visser, R.G.F. - \ 1998
Molecular Breeding 4 (1998). - ISSN 1380-3743 - p. 343 - 358.
|Regeneration of plants from somatic embryos and friable embryogenic callus of cassava.
Raemakers, C.J.J.M. ; Rozeboom, M.G.M. ; Jacobsen, E. ; Visser, R.G.F. - \ 1998
African Journal of Root and Tuber Crops 2 (1998). - p. 238 - 243.
Pinpointing Towards improved transformation and regeneration of cassava (Manihot esculenta Crantz).
Munyikwa, T.R.I. ; Raemakers, C.J.J.M. ; Schreuder, M.M. ; Kok, R. ; Rozeboom, M. ; Jacobsen, E. ; Visser, R.G.F. - \ 1998
Plant Science 153 (1998). - ISSN 0168-9452 - p. 87 - 101.
|Crystal structure at 2.3 A resolution and revised nucleotide sequence of the thermostable cyclodextrin glycosyltransferase from Thermoanaerobacterium thermo-sulfurigenes EM1
Knegtel, R.M.A. ; Wind, R.D. ; Rozeboom, H.J. ; Kalk, K.H. ; Buitelaar, R.M. ; Dijkhuizen, L. ; Dijkstra, B.W. - \ 1996
Journal of Molecular Biology 256 (1996). - ISSN 0022-2836 - p. 611 - 622.
|Twee Cicadellidae nieuw voor de Nederlandse fauna en een herontdekte soort (Homoptera, Auchenorrhyncha).
Bieman, C.F.M. den; Rozeboom, G.J. - \ 1993
Entomologische Berichten 53 (1993). - ISSN 0013-8827 - p. 23 - 25.
|Reproductive isolation in Chloriona planthoppers (Homoptera, Delphacidae).
Gillham, M. ; Rozeboom, J. ; Rijk, C. ; Vrijer, P. de - \ 1992
Proceedings of the Section Experimental and Applied Entomology of the Netherlands Entomological Society 3 (1992). - ISSN 1388-8390 - p. 121 - 122.
De cicaden in bodemvallen (Hemiptera, Homoptera auchenorrhyncha)
Cobben, R.H. ; Rozeboom, G.J. - \ 1983
Natuurhistorisch Maandblad 72 (1983). - ISSN 0028-1107 - p. 102 - 110.
|Notes on Auchenorrhyncha (Homoptera) from pitfall traps in the Gerendal Reserve (Southern part of the Limburg Province)
Cobben, R.H. ; Rozeboom, G.J. - \ 1978
Publicaties van het Natuurhistorisch Genootschap in Limburg 28 (1978)1. - p. 1 - 15.