PubMed Health⌕ Search
Home/Archive/PubMed

PubMed · 16124806

Molecular dynamics of a vanadate-dipeptide complex in aqueous solution.

Michael Bühl
View original source ↗Export metadata ↓

Abstract

Static geometry optimizations and Car-Parrinello molecular dynamics simulations with the BP86 density functional, as well as NMR chemical shift calculations at the GIAO-B3LYP level, have been used to assess structure, speciation, and dynamics of aqueous solutions of the vanadate-glycylglycine complex. According to the simulations, this complex should be formulated as five-coordinate, anionic [VO2(GlyGly')]- (GlyGly' = H2N-CH2-C(O)-N-CH2-CO2). The neutral conjugate acid is unstable in water, where it is deprotonated within a few picoseconds. Six-coordinate structural alternatives, [VO(OH)2(GlyGly')]-, are disfavored energetically and/or entropically. The hydration shell around [VO2(GlyGly')]- in water is characterized in terms of suitable pair correlation functions.

Explore related subjects

GlycylglycineModels, MolecularMolecular StructureSolutionsVanadatesWaterJournal ArticleResearch Support, Non-U.S. Gov't

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Michael Bühl. 2005-09-05. Molecular dynamics of a vanadate-dipeptide complex in aqueous solution.. https://doi.org/10.1021/ic050694i

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed2005

A high-pressure mass spectrometric and density functional theory investigation of the thermochemical properties and structure of protonated dimers and trimers of glycine.

A new modification of pulsed-ionization high-pressure mass spectrometry (PHPMS) has been used to perform equilibrium thermochemical studies for relatively nonvolatile biomolecules such as amino acids. Binding enthalpy and entropy changes have been measured for proton-bound clusters of glycine, which are in good agreement with both theoretical (DFT) results of this work and a previous blackbody infrared dissociation experiment. Experimental data indicate that a number of conformers of the proton-bound dimer of glycine may coexist in the explored temperature range (360-460 K). Several new, conceptually different isomers (two of them zwitterionic) have been found by DFT calculations, one of which is 7 kJ mol(-1) lower in energy than the structure previously reported to be the energy minimum.

Glycylglycine↗
PubMed1985

Kinetic assay of gamma-glutamyltransferase with use of bilirubin oxidase as a coupled enzyme.

We studied the kinetic measurement of gamma-glutamyltransferase (EC.2.3.2.2), coupling the reaction with that catalyzed by bilirubin oxidase (EC 1.3.3.5), which oxidizes and combines a phenylenediamine derivative with an aniline derivative to produce a green pigment. We measured the formation of the pigment kinetically (at lambda max745 nm, epsilon = 75 000 L mol-1 cm-1), with L-gamma-glutamyl-N-hydroxyethylaminoanilide as substrate and N-ethyl-N-hydroxy-3-sulfopropyl)-m-toluidine as a the coupling derivative. The within-run CV for measuring this reaction in samples of normal sera was 2.4%. A calibration plot of the change in absorbance per minute vs enzyme activity concentration showed good proportionality in the range of 0-1300 U/L. The results of this assay correlated well (r = 0.995) with those of the Boehringer method, in which L-gamma-glutamyl-3-carboxy-4-nitroanilide is the substrate. This new, highly sensitive procedure may be adapted to other assays involving phenylenediamine derivates as synthetic substrates.

Glycylglycine↗