Thermophilic xylanase from Thermomyces lanuginosus:: High-resolution X-ray structure and modeling studies

被引:128
作者
Gruber, K
Klintschar, G
Hayn, M
Schlacher, A
Steiner, W
Kratky, C
机构
[1] Graz Univ, Inst Phys Chem, A-8010 Graz, Austria
[2] Graz Univ, Inst Biochem, A-8010 Graz, Austria
[3] Graz Univ Technol, Inst Biotechnol, A-8010 Graz, Austria
关键词
D O I
10.1021/bi980864l
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
The crystal structure of the thermostable xylanase from Thermomyces lanuginosus was determined by single-crystal X-ray diffraction. The protein crystallizes in space group P2(1), a = 40.96(4) Angstrom, b = 52.57(5) Angstrom, c = 50.47 (5) Angstrom, beta = 100.43(5)degrees, Z = 2. Diffraction data were collected at room temperature for a resolution range of 25-1.55 Angstrom, and the structure was solved by molecular replacement with the coordinates of xylanase II from Trichoderma reesei as a search model and refined to a crystallographic R-factor of 0.155 for all observed reflections. The enzyme belongs to the family 11 of glycosyl hydrolases [Henrissat, B., and Bairoch, A. (1993) Biochem. J. 293, 781-788]. pK(a) calculations were performed to assess the protonation state of residues relevant for catalysis and enzyme stability, and a heptaxylan was fitted into the active-site groove by homology modeling, using the published crystal structure of a complex between the Bacillus circulans xylanase and a xylotetraose. Molecular dynamics indicated the central three sugar rings to be tightly bound, whereas the peripheral ones can assume different orientations and conformations, suggesting that the enzyme might also accept xylan chains which are branched at these positions. The reasons for the thermostability of the T. lanuginosus xylanase were analyzed by comparing its crystal structure with known structures of mesophilic family 11 xylanases. It appears that the thermostability is due to the presence of an extra disulfide bridge, as well as to an increase in the density of charged residues throughout the protein.
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页码:13475 / 13485
页数:11
相关论文
共 96 条
  • [1] [Anonymous], [No title captured]
  • [2] CLONING AND TARGETED GENE DISRUPTION OF XYL1, A BETA-1,4-XYLANASE GENE FROM THE MAIZE PATHOGEN COCHLIOBOLUS-CARBONUM
    APEL, PC
    PANACCIONE, DG
    HOLDEN, FR
    WALTON, JD
    [J]. MOLECULAR PLANT-MICROBE INTERACTIONS, 1993, 6 (04) : 467 - 473
  • [3] Closed structure of phosphoglycerate kinase from Thermotoga maritima reveals the catalytic mechanism and determinants of thermal stability
    Auerbach, G
    Huber, R
    Grattinger, M
    Zaiss, K
    Schurig, H
    Jaenicke, R
    Jacob, U
    [J]. STRUCTURE, 1997, 5 (11) : 1475 - 1483
  • [4] THE CCP4 SUITE - PROGRAMS FOR PROTEIN CRYSTALLOGRAPHY
    BAILEY, S
    [J]. ACTA CRYSTALLOGRAPHICA SECTION D-BIOLOGICAL CRYSTALLOGRAPHY, 1994, 50 : 760 - 763
  • [5] ALSCRIPT - A TOOL TO FORMAT MULTIPLE SEQUENCE ALIGNMENTS
    BARTON, GJ
    [J]. PROTEIN ENGINEERING, 1993, 6 (01): : 37 - 40
  • [6] A STRATEGY FOR THE RAPID MULTIPLE ALIGNMENT OF PROTEIN SEQUENCES - CONFIDENCE LEVELS FROM TERTIARY STRUCTURE COMPARISONS
    BARTON, GJ
    STERNBERG, MJE
    [J]. JOURNAL OF MOLECULAR BIOLOGY, 1987, 198 (02) : 327 - 337
  • [7] BEDFORD MR, 1992, PROGR BIOTECHNOL, V7, P361
  • [8] BLUM M, 1987, J APPL CRYSTALLOGR, V21, P235
  • [9] BROCKLEHURST SM, 1993, PROTEIN SCI, V2, P626
  • [10] CHARMM - A PROGRAM FOR MACROMOLECULAR ENERGY, MINIMIZATION, AND DYNAMICS CALCULATIONS
    BROOKS, BR
    BRUCCOLERI, RE
    OLAFSON, BD
    STATES, DJ
    SWAMINATHAN, S
    KARPLUS, M
    [J]. JOURNAL OF COMPUTATIONAL CHEMISTRY, 1983, 4 (02) : 187 - 217