Search

L-lysine was applied to the synthesis of 3-substituted coumarins through the condensation of various salicylaldehyde with reactive methylene compounds in water. In this work, waste minimization, catalyst recovery, simple operation and easier product work-up were achieved.

If considering that the pronouncedly charged halide anions are ubiquitous in the biological world, then it is interesting to ask whether the halogen-ionic bridgesthis term is named by us to describe the interaction motif of a nonbonded halogen ion with two or more electrophiles simultaneouslycommonly exist in biomolecules and how they contribute to the stability and specificity of biomolecular folding and binding? To address these problems, we herein present a particularly systematic investigation on the geometrical profile and the energy landscape of halogen ions interacting with and bridging between polar and charged molecular moieties in small model systems and real crystal structures, by means of ab initio calculation, database survey, continuum electrostatic analysis, and hybrid quantum mechanics/molecular mechanics examination. All of these unequivocally demonstrate that this putative halide motif is broadly distributed in biomolecular systems (>6000) and can confer a substantial stabilization for the architecture of proteins and their complexes with nucleic acids and small ligands. This stabilization energy is estimated to be generally more than 100 kcal·mol−1for gas-phase states or about 20 kcal·mol−1for solution conditions, which is much greater than that found in sophisticated water-mediated (<10 kcal·mol−1) and salt (∼ 3.66 kcal·mol−1) bridges. In this respect, we would expect that the proposed halogen-ionic bridge, which has long been unrecognized in the arena of biological repertoires, could be appreciated in chemistry and biology communities and might be exploited as a new and versatile tool for rational drug design and bioengineering.

Quantitative structureproperty relationships QSPRs have been developed to predict the ion mobility spectrometry IMS drift time tDfor a set of 1481 peptides generated by protease digestion of the Drosophila melanogasterproteome using information directly derived from molecular structures. The relationship between peptide structure and the drift time tDwas constructed by using partial least squares regression PLS, leastsquares support vector machine LSSVM and Gaussian process GP coupled with genetic algorithmvariable selection. Among these models, the linear PLS was incapable of capturing all dependences in this peptide system; nonlinear LSSVM and GP methods presented a good statistical performance on reproducing peptide mobility behavior. Moreover, since GP was able to handling both linear and nonlinearhybrid relationship, it gave a stronger fitting ability and a better predictive power than the LSSVM. Systematic analysis of the GP model showed that diversified properties contribute remarkable effect to the relationship between the drift time and the peptide structure. Particularly, the structural topological information and charge distribution contribute significantly to the drift time of peptides.

Traditional quantitative structure-activity relationship (QSAR) is a term describing a variety of approaches that are of substantial interest for chemistry. Quantitative sequence-activity model (QSAM), applying QSAR strategy to explore sequence-activity/function relationship for biosystems, is greatly meaningful but meanwhile extremely difficult. For biomolecules, high molecular weight, diverse structural morphology and intricate interaction network all bring in traditional QSAR methodologies unprecedented challenges. This article comprehensively reviewed developing process, current state and future perspective of QSAM, concerning its applications into fields of pharmacy, food science, immunology and molecular biology. Besides, discipline-crossing and amalgamation of QSAM with QSAR, bioinformatics and computational biology were also discussed.

In this article, we discuss the application of the Gaussian process GP and other statistical methods PLS, ANN, and SVM for the modeling and prediction of binding affinities between the human amphiphysin SH3 domain and its peptide ligands. Divided physicochemical property scores of amino acids, involving significant hydrogen bond, electronic, hydrophobic, and steric properties, was used to characterize the peptide structures, and quantitative structureaffinity relationship models were then constructed by PLS, ANN, SVM, and GP coupled with genetic algorithmvariable selection. The results show that: i since the significant flexibility and high complexity possessed in polypeptide structures, linear PLS method was incapable of fulfilling a satisfying behavior on SH3 domain binding peptide dataset; ii the overfitting involved in training process has decreased the predictive power of ANN model to some extent; iii both SVM and GP have a good performance for SH3 domain binding peptide dataset. Moreover, by combining linear and nonlinear terms in the covariance function, the GP is capable of handling linear and nonlinearhybrid relationship, and which thus obtained a more stable and predictable model than SVM. Analyses of GP models showed that diversified properties contribute remarkable effect to the interactions between the SH3 domain and the peptides. Particularly, steric property and hydrophobicity of P2, electronic property of P0, and electronic property and hydrogen bond property of P−3in decapeptide P4P3P2P1P0P−1P−2P−3P−4P−5 significantly contribute to the binding affinities of SH3 domainpeptide interactions. © 2008 Wiley Periodicals, Inc. Biopolymers Pept Sci 90:792802, 2008.This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymerswiley.com

The organotin(IV) complexes of N-(2-mercaptophenyl)salicylaldimine,ROCOCH2CH2SnClL(L=OC6H4CH=NC6H4S, R=alkyl), were synthesized by the reaction of 2-alkoxy carbonylethyltin trichlorides with N-(2-mercaptophenyl)salicylaldimine (H2L) in the presence of triethylamine and were characterized by elemental analyses, IR, 1H NMR spectra and X-ray single crystal diffraction. The structural features of these compounds are discussed.

A green and efficient method for the dimeric esterification of various aliphatic primary alcohols is developed (10 examples).

The system L‐His / ionic liquid can be recycled several times with no decrease in yield or rate.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

For Abstract see ChemInform Abstract in Full Text.