more recently medical chemistry research has been focused on proteins that drive and controlcell cycle progression. among them, the cyclin dependent kinases (cdk’s) are a group ofserine/threonine kinases, which rule the transition between successive stages of the cell cycle. theactivity of cdk’s is regulated by multiple mechanisms, including binding to cyclins, which is a broadclass of positive...

: in this work, different levels of theory containing hf, b3lyp, and mp2 with different basis sets such as 6-31g, 6-31g*, 6-311g, 6-311+g, 6-31+g*, 6-31+g are used to predict relative acidity constants of some aniline derivatives. three different kinds of radii containing uahf, bondi, and pauling are used to study how cavity forms change acidity constants. in all cases, dpcm model is used to si...

the results of mndo, am1 and pm3 semi-empirical calculations and hf/6-31g*, mp/6-31g*, mp2/6-311+g**, and b3lyp/6-311g** and qcisd/6-31g* ab initio methods for angle strain and conjugation effects in twist-boat, boat, and half-chair geometries of (z,z,z)-cycloocta-1,3,5-triene indicate that all methods, except pm3, predict wrong ordering of the conformations.

dppc (dipalmitoylphosphatidylcholine) and dmpc (dimyristoylphosphatidylcholine) are taken asphospholipids with an equal polar heads and with the difference in the length of hydrocarbonchains. results obtain from the structural optimization of the isolated dppc and dmpc in the gasphase, at the hartree-fock level of theory by means of sto-3g,3-21g, 6-31g and 6-31g* basissets. the most important d...

The interaction of dopamine and cysteine for formation of 5-S-cysteinyldopamine are investigated at theHartree-Fock level theory. The structural and vibrational properties of 5-S-cysteinyldopamine are studiedat level of HF/6-31G*.Interaction energy ( AE) is calculated -771.6923 Kcal/mol Rotational energy andthermodynamic parameters around two bond have been determined using HF/3-21G. Changes of...

More recently medical chemistry research has been focused on proteins that drive and controlcell cycle progression. Among them, the cyclin dependent kinases (cdk’s) are a group ofserine/threonine kinases, which rule the transition between successive stages of the cell cycle. Theactivity of cdk’s is regulated by multiple mechanisms, including binding to cyclins, which is a broadclass of positive...

The quantitative influence of the choice of energy evaluation method used in the geometry optimization step prior to the calculation of molecular descriptors in QSAR and QSPR models was investigated. A total of 11 energy evaluation methods on three molecular datasets (toxicological compounds, aromatic compounds and PPARgamma agonists) were studied. The methods employed were: MMFF94 s, MM3* with...

One of the fastest steps in the initial decomposition of HFCs under combustion conditions is hydrogen atom abstraction by hydroxyl radicals. We have utilized ab initio quantum mechanics and transition-state theory (TST) to calculate the temperature dependence of rate constants for the reactions of OH with CH4, CH3F, CH2F2, and CHF3. Rate constants calculated using HF/6-31G(d) frequencies and MP...

interaction of meso — tetrakis (p-sulphonato phenyl) porphyrin (hereafter abbreviated to tspp)with na+ has been examined using hf level of theory with 6-31g* basis set. counterpoise (cp)correction has been used to show the extent of the basis set superposition error (bsse) on thepotential energy curves. the numbers of na+ have a significant effect on the calculated potentialenergy curve (includ...

Tacrine (9-amino-1,2,3,4-tetrahydroacridine) as a reversible inhibitor of acetylcholinesterase (AChE),was the first drug for the symptomatic treatment of Alzheimer’s disease (AD). NMR structuredetermination still presents some considerable challenges: the method is limited to systems ofrelatively small molecular mass, data collection times are long, data analysis remains a lengthyprocedure, and...