Development of reliable aqueous solubility models and their application in druglike analysis.

In this work, two reliable aqueous solubility models, ASMS (aqueous solubility based on molecular surface) and ASMS-LOGP (aqueous solubility based on molecular surface using ClogP as a descriptor), were constructed by using atom type classified solvent accessible surface areas and several molecular descriptors for a diverse data set of 1708 molecules. For ASMS (without using ClogP as a descriptor), the leave-one-out q(2) and root-mean-square error (RMSE) were 0.872 and 0.

Genetic algorithm-optimized QSPR models for bioavailability, protein binding, and urinary excretion.

In this work, a genetic algorithm (GA) was applied to build up a set of QSPR (quantitative structure-property relationship) models for human absolute oral bioavailability, plasma protein binding, and urinary excretion using the counts of molecular fragments as descriptors. For a pharmacokinetic property, the consensus score of a set of models (20 or 30) was found to improve the correlation coefficient and reduce the standard error significantly. Key fragments that may boost or reduce pharmacokinetic properties were also identified.

Effects of steroidal allenic phosphonic acid derivatives on the parasitic protists Leishmania donovani, Leishmania mexicana mexicana, and Pneumocystis carinii carinii.

Several pathogenic fungi and protozoa are known to have sterols distinct from those of their mammalian hosts. Of particular interest as targets for drug development are the biosyntheses of the sterols of important parasites such as the kinetoplastid flagellates and the AIDS-associated opportunistic protist Pneumocystis carinii. These pathogens synthesize sterols with an alkyl group at C-24, and some have a double bond at C-22 of the side chain.

An NMR and spin label study of the effects of binding calcium and troponin I inhibitory peptide to cardiac troponin C.

The paramagnetic relaxation reagent, 4-hydroxy-2,2,6,6-tetramethylpiperidinyl-1-oxy (HyTEMPO), was used to probe the surface exposure of methionine residues of recombinant cardiac troponin C (cTnC) in the absence and presence of Ca2+ at the regulatory site (site II), as well as in the presence of the troponin I inhibitory peptide (cTnIp). Methyl resonances of the 10 Met residues of cTnC were chosen as spectral probes because they are thought to play a role in both formation of the N-terminal hydrophobic pocket and in the binding of cTnIp. Proton longitudinal relaxation rates (R1's) of the [13C-methyl] groups in [13C-methyl]Met-labeled cTnC(C35S) were determined using a T1 two-dimensional heteronuclear single- and multiple-quantum coherence pulse sequence.

Assignment and calcium dependence of methionyl epsilon C and epsilon H resonances in cardiac troponin C.

The 10 Met methyl groups in recombinant cardiac troponin (cTnC) were metabolically labeled with [13C-methyl]Met and detected as 10 individual cross-peaks using two-dimensional heteronuclear single- and multiple-quantum coherence (HSMQC) spectroscopy. The epsilon C and epsilon H chemical shifts for all 10 Met residues were sequence-specifically assigned using a combination of HSMQC and systematic conversion of the Met residues to Leu. The only negative functional consequence of these changes was seen when both Met 45 and 81 were mutated.