BioNMR
NMR aggregator & online community since 2003
BioNMR    
Learn or help to learn NMR - get free NMR books!
 

Go Back   BioNMR > Educational resources > Journal club
Advanced Search



Jobs Groups Conferences Literature Pulse sequences Software forums Programs Sample preps Web resources BioNMR issues


Webservers
NMR processing:
MDD
NMR assignment:
Backbone:
Autoassign
MARS
UNIO Match
PINE
Side-chains:
UNIO ATNOS-Ascan
NOEs:
UNIO ATNOS-Candid
UNIO Candid
ASDP
Structure from NMR restraints:
Ab initio:
GeNMR
Cyana
XPLOR-NIH
ASDP
UNIO ATNOS-Candid
UNIO Candid
Fragment-based:
BMRB CS-Rosetta
Rosetta-NMR (Robetta)
Template-based:
GeNMR
I-TASSER
Refinement:
Amber
Structure from chemical shifts:
Fragment-based:
WeNMR CS-Rosetta
BMRB CS-Rosetta
Homology-based:
CS23D
Simshift
Torsion angles from chemical shifts:
Preditor
TALOS
Promega- Proline
Secondary structure from chemical shifts:
CSI (via RCI server)
TALOS
MICS caps, β-turns
d2D
PECAN
Flexibility from chemical shifts:
RCI
Interactions from chemical shifts:
HADDOCK
Chemical shifts re-referencing:
Shiftcor
UNIO Shiftinspector
LACS
CheckShift
RefDB
NMR model quality:
NOEs, other restraints:
PROSESS
PSVS
RPF scores
iCing
Chemical shifts:
PROSESS
CheShift2
Vasco
iCing
RDCs:
DC
Anisofit
Pseudocontact shifts:
Anisofit
Protein geomtery:
Resolution-by-Proxy
PROSESS
What-If
iCing
PSVS
MolProbity
SAVES2 or SAVES4
Vadar
Prosa
ProQ
MetaMQAPII
PSQS
Eval123D
STAN
Ramachandran Plot
Rampage
ERRAT
Verify_3D
Harmony
Quality Control Check
NMR spectrum prediction:
FANDAS
MestReS
V-NMR
Flexibility from structure:
Backbone S2
Methyl S2
B-factor
Molecular dynamics:
Gromacs
Amber
Antechamber
Chemical shifts prediction:
From structure:
Shiftx2
Sparta+
Camshift
CH3shift- Methyl
ArShift- Aromatic
ShiftS
Proshift
PPM
CheShift-2- Cα
From sequence:
Shifty
Camcoil
Poulsen_rc_CS
Disordered proteins:
MAXOCC
Format conversion & validation:
CCPN
From NMR-STAR 3.1
Validate NMR-STAR 3.1
NMR sample preparation:
Protein disorder:
DisMeta
Protein solubility:
camLILA
ccSOL
Camfold
camGroEL
Zyggregator
Isotope labeling:
UPLABEL
Solid-state NMR:
sedNMR


Reply
Thread Tools Search this Thread Rate Thread Display Modes
  #1  
Unread 08-22-2010, 03:01 AM
nmrlearner's Avatar
Senior Member
 
Join Date: Jan 2005
Posts: 17,570
Points: 193,617, Level: 100
Points: 193,617, Level: 100 Points: 193,617, Level: 100 Points: 193,617, Level: 100
Level up: 0%, 0 Points needed
Level up: 0% Level up: 0% Level up: 0%
Activity: 50.7%
Activity: 50.7% Activity: 50.7% Activity: 50.7%
Last Achievements
Award-Showcase
NMR Credits: 0
NMR Points: 193,617
Downloads: 0
Uploads: 0
Default 19F-NMR study on the pH-dependent regioselectivity and rate of the ortho-hydroxylatio

19F-NMR study on the pH-dependent regioselectivity and rate of the ortho-hydroxylation of 3-fluorophenol by phenol hydroxylase from Trichosporon cutaneum. Implications for the reaction mechanism.

Related Articles 19F-NMR study on the pH-dependent regioselectivity and rate of the ortho-hydroxylation of 3-fluorophenol by phenol hydroxylase from Trichosporon cutaneum. Implications for the reaction mechanism.

Eur J Biochem. 1993 Dec 1;218(2):345-53

Authors: Peelen S, Rietjens IM, van Berkel WJ, van Workum WA, Vervoort J

The regioselectivity and rate of the ortho-hydroxylation of 3-fluorophenol by phenol hydroxylase from Trichosporon cutaneum (EC 1.14.13.7) was studied using 19F-NMR. The regioselective hydroxylation as well as the rate of ortho-hydroxylation are pH dependent with a pKa of 6.5. At pH values below 6.5, 3-fluorophenol preferentially becomes hydroxylated at the C6 ortho position, resulting in a maximum C6/C2 hydroxylation ratio of 6.7. Upon increasing the pH, the total rate of conversion increases. Also, the C2 ortho-hydroxylation increases relatively to the C6 ortho-hydroxylation and yields a minimum C6/C2 hydroxylation ratio of 2.2 at pH values above 7.5. Based on data from 19F-NMR binding studies and molecular orbital calculations, a hypothesis is put forward which explains the pH-dependent effects observed. A mechanism is proposed involving an active-site amino acid residue acting as a base in the reduced form of the protein. Deprotonation of this residue results in hydrogen bond formation with the hydroxyl moiety of the phenolic substrate, leading to (partial) deprotonation of the substrate. Molecular orbital calculations demonstrate that such a (partial) deprotonation increases (a) the overall reactivity of 3-fluorophenol for an electrophilic attack and (b) the reactivity of C2 relative to the C6 position. The hypothesis may explain the decrease in the C6/C2 hydroxylation ratio. Furthermore the increased amount of ortho-hydroxylated products formed with increasing pH can also be explained by this hypothesis.

PMID: 8269923 [PubMed - indexed for MEDLINE]



Source: PubMed
Reply With Quote


Did you find this post helpful? Yes | No

Reply
Similar Threads
Thread Thread Starter Forum Replies Last Post
Sequence-Dependent Enrichment of a Model Phosphopeptide: A Combined MALDI-TOF and NMR Study.
Sequence-Dependent Enrichment of a Model Phosphopeptide: A Combined MALDI-TOF and NMR Study. Sequence-Dependent Enrichment of a Model Phosphopeptide: A Combined MALDI-TOF and NMR Study. Anal Chem. 2011 Mar 23; Authors: Lucre?ce M, Emmanuelle S, Fabienne B, Sandrine S, Olivier L, Ge?rard B The goal of this study was to detect and quantify by MALDI-TOF MS the phosphorylation of a peptide containing the recognition motif of the Protein Kinase C (PKC). Such model peptide can be used as a phosphorylation probe to follow intracellular...
nmrlearner Journal club 0 03-25-2011 06:34 PM
[NMR paper] NMR structural analysis of an analog of an intermediate formed in the rate-determinin
NMR structural analysis of an analog of an intermediate formed in the rate-determining step of one pathway in the oxidative folding of bovine pancreatic ribonuclease A: automated analysis of 1H, 13C, and 15N resonance assignments for wild-type and mutant forms. http://www.ncbi.nlm.nih.gov/corehtml/query/egifs/http:--pubs.acs.org-images-acspubs.jpg Related Articles NMR structural analysis of an analog of an intermediate formed in the rate-determining step of one pathway in the oxidative folding of bovine pancreatic ribonuclease A: automated analysis of 1H, 13C, and 15N resonance...
nmrlearner Journal club 0 08-22-2010 03:03 PM
[NMR paper] Solvent polarity-dependent structural refolding: a CD and NMR study of a 15 residue p
Solvent polarity-dependent structural refolding: a CD and NMR study of a 15 residue peptide. Related Articles Solvent polarity-dependent structural refolding: a CD and NMR study of a 15 residue peptide. Proteins. 1995 Oct;23(2):196-203 Authors: Graf von Stosch A, Jiménez MA, Kinzel V, Reed J A close association between the HIV surface protein gp120 and the CD4 T cell receptor initiates the viral multiplication cycle. A 15 amino acid peptide (LAV) within the CD4 binding domain of gp 120 has been shown to retain receptor binding ability. The...
nmrlearner Journal club 0 08-22-2010 03:50 AM
[NMR paper] 1H- and 13C-NMR investigation of redox-state-dependent and temperature-dependent conf
1H- and 13C-NMR investigation of redox-state-dependent and temperature-dependent conformation changes in horse cytochrome c. http://www.ncbi.nlm.nih.gov/corehtml/query/egifs/http:--www3.interscience.wiley.com-aboutus-images-wiley_interscience_pubmed_logo_FREE_120x27.gif Related Articles 1H- and 13C-NMR investigation of redox-state-dependent and temperature-dependent conformation changes in horse cytochrome c. Eur J Biochem. 1993 Feb 1;211(3):555-62 Authors: Turner DL, Williams RJ The redox-state dependent changes in chemical shift, which have...
nmrlearner Journal club 0 08-21-2010 11:53 PM
[NMR paper] 13C magic angle spinning NMR study of the light-induced and temperature-dependent cha
13C magic angle spinning NMR study of the light-induced and temperature-dependent changes in Rhodobacter sphaeroides R26 reaction centers enriched in tyrosine. Related Articles 13C magic angle spinning NMR study of the light-induced and temperature-dependent changes in Rhodobacter sphaeroides R26 reaction centers enriched in tyrosine. Biochemistry. 1992 Nov 17;31(45):11038-49 Authors: Fischer MR, de Groot HJ, Raap J, Winkel C, Hoff AJ, Lugtenburg J Solid-state 13C magic angle spinning (MAS) NMR has been used to investigate...
nmrlearner Journal club 0 08-21-2010 11:45 PM
[NMR paper] NMR analysis of regioselectivity in dephosphorylation of a triphosphotyrosyl dodecape
NMR analysis of regioselectivity in dephosphorylation of a triphosphotyrosyl dodecapeptide autophosphorylation site of the insulin receptor by a catalytic fragment of LAR phosphotyrosine phosphatase. http://www.ncbi.nlm.nih.gov/corehtml/query/egifs/http:--www3.interscience.wiley.com-aboutus-images-wiley_interscience_pubmed_logo_FREE_120x27.gif http://www.ncbi.nlm.nih.gov/corehtml/query/egifs/http:--www.pubmedcentral.nih.gov-corehtml-pmc-pmcgifs-pubmed-pmc.gif Related Articles NMR analysis of regioselectivity in dephosphorylation of a triphosphotyrosyl dodecapeptide...
nmrlearner Journal club 0 08-21-2010 11:45 PM


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



BioNMR advertisements to pay for website hosting and domain registration. Nobody does it for us.



Powered by vBulletin® Version 3.7.3
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.
Copyright, BioNMR.com, 2003-2013
Search Engine Friendly URLs by vBSEO 3.6.0

All times are GMT. The time now is 11:51 AM.


Map