3PBV

Crystal structure of the mutant I96T of orotidine 5'-monophosphate decarboxylase from Methanobacterium thermoautotrophicum complexed with 6-azauridine 5'-monophosphate


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.3 Å
  • R-Value Free: 0.183 
  • R-Value Work: 0.161 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Mechanism of the orotidine 5'-monophosphate decarboxylase-catalyzed reaction: importance of residues in the orotate binding site.

Iiams, V.Desai, B.J.Fedorov, A.A.Fedorov, E.V.Almo, S.C.Gerlt, J.A.

(2011) Biochemistry 50: 8497-8507

  • DOI: 10.1021/bi2012355
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • The reaction catalyzed by orotidine 5'-monophosphate decarboxylase (OMPDC) is accompanied by exceptional values for rate enhancement (k(cat)/k(non) = 7.1 × 10(16)) and catalytic proficiency [(k(cat)/K(M))/k(non) = 4.8 × 10(22) M(-1)]. Although a stab ...

    The reaction catalyzed by orotidine 5'-monophosphate decarboxylase (OMPDC) is accompanied by exceptional values for rate enhancement (k(cat)/k(non) = 7.1 × 10(16)) and catalytic proficiency [(k(cat)/K(M))/k(non) = 4.8 × 10(22) M(-1)]. Although a stabilized vinyl carbanion/carbene intermediate is located on the reaction coordinate, the structural strategies by which the reduction in the activation energy barrier is realized remain incompletely understood. This laboratory recently reported that "substrate destabilization" by Asp 70 in the OMPDC from Methanothermobacter thermoautotrophicus (MtOMPDC) lowers the activation energy barrier by ∼5 kcal/mol (contributing ~2.7 × 10(3) to the rate enhancement) [Chan, K. K., Wood, B. M., Fedorov, A. A., Fedorov, E. V., Imker, H. J., Amyes, T. L., Richard, J. P., Almo, S. C., and Gerlt, J. A. (2009) Biochemistry 48, 5518-5531]. We now report that substitutions of hydrophobic residues in a pocket proximal to the carboxylate group of the substrate (Ile 96, Leu 123, and Val 155) with neutral hydrophilic residues decrease the value of k(cat) by as much as 400-fold but have a minimal effect on the value of k(ex) for exchange of H6 of the FUMP product analogue with solvent deuterium; we hypothesize that this pocket destabilizes the substrate by preventing hydration of the substrate carboxylate group. We also report that substitutions of Ser 127 that is proximal to O4 of the orotate ring decrease the value of k(cat)/K(M), with the S127P substitution that eliminates hydrogen bonding interactions with O4 producing a 2.5 × 10(6)-fold reduction; this effect is consistent with delocalization of the negative charge of the carbanionic intermediate on O4 that produces an anionic carbene intermediate and thereby provides a structural strategy for stabilization of the intermediate. These observations provide additional information about the identities of the active site residues that contribute to the rate enhancement and, therefore, insights into the structural strategies for catalysis.


    Organizational Affiliation

    Departments of Biochemistry and Chemistry, University of Illinois, Urbana, Illinois 61801, United States.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Orotidine 5'-monophosphate decarboxylase
A, B
228Methanothermobacter thermautotrophicus (strain ATCC 29096 / DSM 1053 / JCM 10044 / NBRC 100330 / Delta H)Mutation(s): 2 
Gene Names: pyrF
EC: 4.1.1.23
Find proteins for O26232 (Methanothermobacter thermautotrophicus (strain ATCC 29096 / DSM 1053 / JCM 10044 / NBRC 100330 / Delta H))
Go to UniProtKB:  O26232
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
GOL
Query on GOL

Download SDF File 
Download CCD File 
A
GLYCEROL
GLYCERIN; PROPANE-1,2,3-TRIOL
C3 H8 O3
PEDCQBHIVMGVHV-UHFFFAOYSA-N
 Ligand Interaction
UP6
Query on UP6

Download SDF File 
Download CCD File 
A, B
6-AZA URIDINE 5'-MONOPHOSPHATE
6-AZA-UMP
C8 H12 N3 O9 P
LRVZOSYMNMNQFR-SHUUEZRQSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.3 Å
  • R-Value Free: 0.183 
  • R-Value Work: 0.161 
  • Space Group: P 1 21 1
Unit Cell:
Length (Å)Angle (°)
a = 59.789α = 90.00
b = 63.948β = 115.47
c = 61.636γ = 90.00
Software Package:
Software NamePurpose
ADSCdata collection
DENZOdata reduction
BALBESphasing
SCALEPACKdata scaling
PHENIXrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2011-09-21
    Type: Initial release
  • Version 1.1: 2011-10-12
    Type: Database references
  • Version 1.2: 2011-10-19
    Type: Database references