1D7L

STRUCTURE-FUNCTION CORRELATIONS OF THE REACTION OF REDUCED NICOTINAMIDE ANALOGS WITH P-HYDROXYBENZOATE HYDROXYLASE SUBSTITUTED WITH A SERIES OF 8-SUBSTITUTED FLAVINS


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.2 Å
  • R-Value Free: 0.235 
  • R-Value Work: 0.184 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Structure-function correlations of the reaction of reduced nicotinamide analogues with p-hydroxybenzoate hydroxylase substituted with a series of 8-substituted flavins.

Ortiz-Maldonado, M.Gatti, D.Ballou, D.P.Massey, V.

(1999) Biochemistry 38: 16636-16647


  • PubMed Abstract: 
  • Structural and kinetic studies have revealed two flavin conformations in p-hydroxybenzoate hydroxylase (PHBH), the in-position and the out-position. Conversion between these two conformations is believed to be essential during catalysis. Although sub ...

    Structural and kinetic studies have revealed two flavin conformations in p-hydroxybenzoate hydroxylase (PHBH), the in-position and the out-position. Conversion between these two conformations is believed to be essential during catalysis. Although substrate hydroxylation occurs while the flavin in PHBH is in the in-conformation, the position of the flavin during reduction by NADPH is uncertain. To investigate the catalytic importance of the out-conformation of the flavin and to clarify the mechanism of flavin reduction in PHBH, we report quantitative structure-reactivity relationships (QSAR) using PHBH substituted separately with nine derivatives of FAD modified in the 8-position and four dihydronicotinamide analogues as reducing agents. The 8-position of the FAD isoalloxazine ring was chosen for modification because in PHBH it has minimal interactions with the protein and is accessible to solvent. The chemical sequence of events during catalysis by PHBH was not altered when using any of the modified flavins, and normal products were obtained. Although the rate of reduction of PHBH reconstituted with flavin derivatives is expected to be dependent on the redox potential of the flavin, no strict correlation was observed. Instead, the rate of reduction correlated with the kappa-substituent constant, which is based on size and hydrophobicity of the 8-substituent on the FAD. Substituents that sterically hinder attainment of the out-conformation decreased the rate of flavin reduction much more than expected on the basis of the redox potential of the flavin. The results of this QSAR analysis are consistent with the hypothesis that the flavin in PHBH must move to the out-conformation for proper formation of the charge-transfer complex between NADPH and FAD that is necessary for rapid flavin reduction.


    Organizational Affiliation

    Department of Biological Chemistry, University of Michigan, Ann Arbor 48109-0606, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
P-HYDROXYBENZOATE HYDROXYLASE
A
394Pseudomonas aeruginosa (strain ATCC 15692 / DSM 22644 / CIP 104116 / JCM 14847 / LMG 12228 / 1C / PRS 101 / PAO1)Mutation(s): 0 
Gene Names: pobA
EC: 1.14.13.2
Find proteins for P20586 (Pseudomonas aeruginosa (strain ATCC 15692 / DSM 22644 / CIP 104116 / JCM 14847 / LMG 12228 / 1C / PRS 101 / PAO1))
Go to UniProtKB:  P20586
Small Molecules
Ligands 3 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
SO4
Query on SO4

Download SDF File 
Download CCD File 
A
SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
 Ligand Interaction
PHB
Query on PHB

Download SDF File 
Download CCD File 
A
P-HYDROXYBENZOIC ACID
C7 H6 O3
FJKROLUGYXJWQN-UHFFFAOYSA-N
 Ligand Interaction
RFL
Query on RFL

Download SDF File 
Download CCD File 
A
8-DEMETHYL-8-DIMETHYLAMINO-FLAVIN-ADENINE-DINUCLEOTIDE
C28 H36 N10 O15 P2
UXOZEHHQWXVTPI-MZWSMYJRSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.2 Å
  • R-Value Free: 0.235 
  • R-Value Work: 0.184 
  • Space Group: C 2 2 21
Unit Cell:
Length (Å)Angle (°)
a = 70.802α = 90.00
b = 145.477β = 90.00
c = 86.966γ = 90.00
Software Package:
Software NamePurpose
SDMSdata reduction
SDMSdata scaling
CNSphasing
CNSrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2000-01-21
    Type: Initial release
  • Version 1.1: 2008-04-27
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Derived calculations, Version format compliance