PMID- 10508789
OWN - NLM
STAT- MEDLINE
DCOM- 19991215
LR  - 20190915
IS  - 0969-2126 (Print)
IS  - 0969-2126 (Linking)
VI  - 7
IP  - 9
DP  - 1999 Sep 15
TI  - Crystal structure and mechanism of a carbon-carbon bond hydrolase.
PG  - 1023-33
AB  - BACKGROUND: Fumarylacetoacetate hydrolase (FAH) catalyzes the final step of
      tyrosine and phenylalanine catabolism, the hydrolytic cleavage of a carbon-carbon
      bond in fumarylacetoacetate, to yield fumarate and acetoacetate. FAH has no known
      sequence homologs and functions by an unknown mechanism. Carbon-carbon hydrolysis
      reactions are essential for the human metabolism of aromatic amino acids. FAH
      deficiency causes the fatal metabolic disease hereditary tyrosinemia type I.
      Carbon-carbon bond hydrolysis is also important in the microbial metabolism of
      aromatic compounds as part of the global carbon cycle. RESULTS: The FAH crystal
      structure has been determined by rapid, automated analysis of multiwavelength
      anomalous diffraction data. The FAH polypeptide folds into a 120-residue
      N-terminal domain and a 300-residue C-terminal domain. The C-terminal domain
      defines an unusual beta-strand topology and a novel 'mixed beta-sandwich roll'
      structure. The structure of FAH complexed with its physiological products was
      also determined. This structure reveals fumarate binding near the entrance to the
      active site and acetoacetate binding to an octahedrally coordinated calcium ion
      located in close proximity to a Glu-His dyad. CONCLUSIONS: FAH represents the
      first structure of a hydrolase that acts specifically on carbon-carbon bonds. FAH
      also defines a new class of metalloenzymes characterized by a unique alpha/beta
      fold. A mechanism involving a Glu-His-water catalytic triad is suggested based on
      structural observations, sequence conservation and mutational analysis. The
      histidine imidazole group is proposed to function as a general base. The Ca(2+)
      is proposed to function in binding substrate, activating the nucleophile and
      stabilizing a carbanion leaving group. An oxyanion hole formed from sidechains is
      proposed to stabilize a tetrahedral alkoxide transition state. The proton
      transferred to the carbanion leaving group is proposed to originate from a lysine
      sidechain. The results also reveal the molecular basis for mutations causing the 
      hereditary tyrosinemia type 1.
FAU - Timm, D E
AU  - Timm DE
AD  - Department of Biochemistry and Molecular Biology Indiana University School of
      Medicine 635 Barnhill Drive, Indianapolis, Indiana 46202, USA. dtimm@iupui.edu
FAU - Mueller, H A
AU  - Mueller HA
FAU - Bhanumoorthy, P
AU  - Bhanumoorthy P
FAU - Harp, J M
AU  - Harp JM
FAU - Bunick, G J
AU  - Bunick GJ
LA  - eng
SI  - PDB/1QCN
SI  - PDB/1QCO
SI  - PDB/1QQJ
GR  - DK54738/DK/NIDDK NIH HHS/United States
GR  - GM29818/GM/NIGMS NIH HHS/United States
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PT  - Research Support, U.S. Gov't, Non-P.H.S.
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - United States
TA  - Structure
JT  - Structure (London, England : 1993)
JID - 101087697
RN  - 0 (Amino Acids)
RN  - 059QF0KO0R (Water)
RN  - 4QD397987E (Histidine)
RN  - 7440-44-0 (Carbon)
RN  - EC 3.- (Hydrolases)
RN  - EC 3.7.1.2 (fumarylacetoacetase)
SB  - IM
MH  - Amino Acids/metabolism
MH  - Binding Sites
MH  - Carbon/*chemistry
MH  - Catalytic Domain
MH  - Crystallography, X-Ray
MH  - Dimerization
MH  - Histidine
MH  - Humans
MH  - Hydrolases/*chemistry/metabolism
MH  - Hydrolysis
MH  - Models, Molecular
MH  - Protein Conformation
MH  - Protein Folding
MH  - Water
EDAT- 1999/10/06 00:00
MHDA- 1999/10/06 00:01
CRDT- 1999/10/06 00:00
PHST- 1999/10/06 00:00 [pubmed]
PHST- 1999/10/06 00:01 [medline]
PHST- 1999/10/06 00:00 [entrez]
AID - S0969-2126(99)80170-1 [pii]
AID - 10.1016/s0969-2126(99)80170-1 [doi]
PST - ppublish
SO  - Structure. 1999 Sep 15;7(9):1023-33. doi: 10.1016/s0969-2126(99)80170-1.