Crystal structure of nitrile hydratase reveals a novel iron centre in a novel fold

被引:280
作者
Huang, WJ
Jia, J
Cummings, J
Nelson, M
Schneider, G
Lindqvist, Y
机构
[1] KAROLINSKA INST,DEPT MED BIOCHEM & BIOPHYS,S-17177 STOCKHOLM,SWEDEN
[2] DUPONT CO INC,CENT RES & DEV,WILMINGTON,DE 19880
关键词
iron centre; metalloenzyme; nitrile hydratase; non-heme iron; protein crystallography;
D O I
10.1016/S0969-2126(97)00223-2
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
Background: Nitrile hydratases are unusual metalloenzymes that catalyze the hydration of nitriles to their corresponding amides. They are used as biocatalysts in acrylamide production, one of the few commercial scale bioprocesses, as well as in environmental remediation for the removal of nitriles from waste streams. Nitrile hydratases are composed of two subunits, alpha and beta, and they contain one iron atom per cup unit. We have determined the crystal structure of photoactivated iron-containing nitrile hydratase from Rhodococcus sp. R312 to 2.65 Angstrom resolution as a first step in the elucidation of its catalytic mechanism. Results: The a subunit consists of a long N-terminal arm and a C-terminal domain that forms a novel fold. This fold can be described as a four layered structure, alpha-beta-beta-alpha, with unusual connectivities between the beta strands. The beta subunit also contains a long N-terminal extension, a helical domain, and a C-terminal domain that folds into a beta roll. The two subunits form a tight heterodimer that is the functional unit of the enzyme. The active site is located in a cavity at the subunit-subunit interface. The iron centre is formed by residues from the alpha subunit only-three cysteine thiolates and two mainchain amide nitrogen atoms are ligands. Conclusions: Nitrile hydratases contain a novel iron centre with a structure not previously observed in proteins; it resembles a hybrid of the iron centres of heme and Fe-S proteins. The tow-spin electronic configuration presumably results in part from two Fe-amide nitrogen bonds. The structure is consistent with the metal ion having a role as a Lewis acid in the catalytic reaction.
引用
收藏
页码:691 / 699
页数:9
相关论文
共 41 条
  • [1] [Anonymous], ACTA CRYSTALLOGR D
  • [2] SOLUTION STRUCTURE AND DNA-BINDING PROPERTIES OF A THERMOSTABLE PROTEIN FROM THE ARCHAEON SULFOLOBUS-SOLFATARICUS
    BAUMANN, H
    KNAPP, S
    LUNDBACK, T
    LADENSTEIN, R
    HARD, T
    [J]. NATURE STRUCTURAL BIOLOGY, 1994, 1 (11): : 808 - 819
  • [3] Resonance Raman spectroscopy of nitrile hydratase, a novel iron - Sulfur enzyme
    Brennan, BA
    Cummings, JG
    Chase, DB
    Turner, IM
    Nelson, MJ
    [J]. BIOCHEMISTRY, 1996, 35 (31) : 10068 - 10077
  • [4] Nitrile hydratase from Rhodococcus rhodochrous J1 contains a non-corrin cobalt ion with two sulfur ligands
    Brennan, BA
    Alms, G
    Nelson, MJ
    Durney, LT
    Scarrow, RC
    [J]. JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1996, 118 (38) : 9194 - 9195
  • [5] FREE R-VALUE - A NOVEL STATISTICAL QUANTITY FOR ASSESSING THE ACCURACY OF CRYSTAL-STRUCTURES
    BRUNGER, AT
    [J]. NATURE, 1992, 355 (6359) : 472 - 475
  • [6] CRYSTALLOGRAPHIC R-FACTOR REFINEMENT BY MOLECULAR-DYNAMICS
    BRUNGER, AT
    KURIYAN, J
    KARPLUS, M
    [J]. SCIENCE, 1987, 235 (4787) : 458 - 460
  • [7] SYNTHESIS AND BASE HYDROLYSIS OF PENTAAMMINE N,N-DIMETHYLFORMAMIDE AND ACETONITRILE COMPLEXES OF RH(III) AND IR(III)
    CURTIS, NJ
    SARGESON, AM
    [J]. JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1984, 106 (03) : 625 - 630
  • [8] An implicit TRIPLE effect in Mims pulsed ENDOR: A sensitive new technique for determining signs of hyperfine couplings
    Doan, PE
    Nelson, MJ
    Jin, HY
    Hoffmann, BM
    [J]. JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1996, 118 (29) : 7014 - 7015
  • [9] CHARACTERIZATION OF NITRILE HYDRATASE GENES CLONED BY DNA SCREEING FROM RHODOCOCCUS-ERYTHROPOLIS
    DURAN, R
    NISHIYAMA, M
    HORINOUCHI, S
    BEPPU, T
    [J]. BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY, 1993, 57 (08) : 1323 - 1328
  • [10] ACCURATE BOND AND ANGLE PARAMETERS FOR X-RAY PROTEIN-STRUCTURE REFINEMENT
    ENGH, RA
    HUBER, R
    [J]. ACTA CRYSTALLOGRAPHICA SECTION A, 1991, 47 : 392 - 400