1LH0

Crystal Structure of Salmonella typhimurium OMP Synthase in Complex with MGPRPP and Orotate


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2 Å
  • R-Value Free: 0.242 
  • R-Value Work: 0.205 

wwPDB Validation 3D Report Full Report


This is version 1.3 of the entry. See complete history

Literature

Structure of Salmonella typhimurium OMP Synthase in a Complete Substrate Complex.

Grubmeyer, C.Hansen, M.R.Fedorov, A.A.Almo, S.C.

(2012) Biochemistry 51: 4397-4405

  • DOI: 10.1021/bi300083p

  • PubMed Abstract: 
  • Dimeric Salmonella typhimurium orotate phosphoribosyltransferase (OMP synthase, EC 2.4.2.10), a key enzyme in de novo pyrimidine nucleotide synthesis, has been cocrystallized in a complete substrate E·MgPRPP·orotate complex and the structure determin ...

    Dimeric Salmonella typhimurium orotate phosphoribosyltransferase (OMP synthase, EC 2.4.2.10), a key enzyme in de novo pyrimidine nucleotide synthesis, has been cocrystallized in a complete substrate E·MgPRPP·orotate complex and the structure determined to 2.2 Å resolution. This structure resembles that of Saccharomyces cerevisiae OMP synthase in showing a dramatic and asymmetric reorganization around the active site-bound ligands but shares the same basic topology previously observed in complexes of OMP synthase from S. typhimurium and Escherichia coli. The catalytic loop (residues 99-109) contributed by subunit A is reorganized to close the active site situated in subunit B and to sequester it from solvent. Furthermore, the overall structure of subunit B is more compact, because of movements of the amino-terminal hood and elements of the core domain. The catalytic loop of subunit B remains open and disordered, and subunit A retains the more relaxed conformation observed in loop-open S. typhimurium OMP synthase structures. A non-proline cis-peptide formed between Ala71 and Tyr72 is seen in both subunits. The loop-closed catalytic site of subunit B reveals that both the loop and the hood interact directly with the bound pyrophosphate group of PRPP. In contrast to dimagnesium hypoxanthine-guanine phosphoribosyltransferases, OMP synthase contains a single catalytic Mg(2+) in the closed active site. The remaining pyrophosphate charges of PRPP are neutralized by interactions with Arg99A, Lys100B, Lys103A, and His105A. The new structure confirms the importance of loop movement in catalysis by OMP synthase and identifies several additional movements that must be accomplished in each catalytic cycle. A catalytic mechanism based on enzymic and substrate-assisted stabilization of the previously documented oxocarbenium transition state structure is proposed.


    Related Citations: 
    • Crystal structure of orotate phosphoribosyltransferase
      Scapin, G.,Grubmeyer, C.,Sacchettini, J.C.
      (1994) Biochemistry 33: 1287
    • The crystal structure of the orotate phosphoribosyltransferase complexed with orotate and alpha-D-5-phosphoribosyl-1-pyrophosphate
      Scapin, G.,Ozturk, D.H.,Grubmeyer, C.,Sacchettini, J.C.
      (1995) Biochemistry 34: 10744


    Organizational Affiliation

    Department of Biochemistry and Fels Research Institute, Temple University School of Medicine, Philadelphia, Pennsylvania 19140, United States. ctg@temple.edu




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
OMP synthase
A, B
213Salmonella typhimurium (strain LT2 / SGSC1412 / ATCC 700720)Gene Names: pyrE
EC: 2.4.2.10
Find proteins for P08870 (Salmonella typhimurium (strain LT2 / SGSC1412 / ATCC 700720))
Go to UniProtKB:  P08870
Small Molecules
Ligands 3 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
PRP
Query on PRP

Download SDF File 
Download CCD File 
B
ALPHA-PHOSPHORIBOSYLPYROPHOSPHORIC ACID
C5 H13 O14 P3
PQGCEDQWHSBAJP-TXICZTDVSA-N
 Ligand Interaction
MG
Query on MG

Download SDF File 
Download CCD File 
B
MAGNESIUM ION
Mg
JLVVSXFLKOJNIY-UHFFFAOYSA-N
 Ligand Interaction
ORO
Query on ORO

Download SDF File 
Download CCD File 
A, B
OROTIC ACID
C5 H4 N2 O4
PXQPEWDEAKTCGB-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2 Å
  • R-Value Free: 0.242 
  • R-Value Work: 0.205 
  • Space Group: C 2 2 2
Unit Cell:
Length (Å)Angle (°)
a = 105.570α = 90.00
b = 154.230β = 90.00
c = 52.600γ = 90.00
Software Package:
Software NamePurpose
SCALEPACKdata scaling
DENZOdata reduction
CNSrefinement
EPMRphasing

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2002-05-08
    Type: Initial release
  • Version 1.1: 2008-04-28
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance
  • Version 1.3: 2012-10-17
    Type: Database references