Conformational flexibility of cyclen controlled by complexation with Ni( ii ) and Cu( as evidenced structural studies.

for better understanding of conformational stability of the dipeptide model hco—gly—l—leu—nh2,ab initio and dft computations at hf/6-31g(4 6-311++g(d,p) and b3lyp/6-31g(d) levels oftheory were carried out. geometry optimization of the dipeptide within the leucine (leu) side chainangles (x2 ,x2) resulted in three stable conformations as followings: anti-anti, the most stable one,(xi = 180°, x2 =...

bcn compounds have been researched theoretically and experimentally widely. in this paper, weintroduce the theoretical prediction of ternary b-c-n compounds. nmr spectroscopy was employedextensively to study these ternary nanostructures. we discuss the utilization of chemical shiftinformation as well as ab initio calculations of nuclear shielding for h20134c9n4 structuredetermination. we calcul...

conformational properties of n-aryl-1-azacyclooctan-5- ones with a p-methyl, m-methyl, and p-methoxy group as a substituent have been studied by 1h-nmr, 13c-nmr and ir spectroscopies. transannular interaction of the two functional groups have been examined from the ring inversion barriers and the carbonyl vibrational frequencies with reference to the corresponding data of the respective monofun...

albumin has a fundamental role in human body. its main tasks in blood are to regulate osmotic blood pressure, maintaining the ph, and transporting metabolites and drugs throughout the vascular system.  pharmacological studies of the interaction of drugs on hsa are important due to structural and functional changes of this vital protein; thus, here in this research the effect of valproate as a c...

Protein amyloid aggregation has been widely observed to occur and plays important roles in both physiological processes pathological diseases. Remarkably, aggregates assembled by native proteins gain a variety of different biological activities, which cannot be adopted the unassembled protein alone. Thus, it is investigate molecular basis self-assembly how aggregated structure determines its fu...

Many diseases are believed to be related to abnormal protein folding. In the first step of such pathogenic structural changes, misfolding occurs in regions important for the stability of the native structure. This destabilizes the normal protein conformation, while exposing the previously hidden aggregation-prone regions, leading to subsequent errors in the folding pathway. Sites involved in th...

Prion proteins were initially associated with diseases such as Creutzfeldt Jakob and transmissible spongiform encephalopathies. However, deeper research revealed them as versatile tools, exploited by the cells to execute fascinating functions, acting as epigenetic elements or building membrane free compartments in eukaryotes. One of the most intriguing properties of prion proteins is their abil...

The key event in prion diseases seems to be the conversion of the prion protein PrP from its normal cellular isoform (PrP(C)) to an aberrant "scrapie" isoform (PrP(Sc)). Earlier studies have detected no covalent modification in the scrapie isoform and have concluded that the PrP(C) --> PrP(Sc) conversion is a purely conformational transition involving no chemical reactions. However, a reexamina...

Features of homologous relationship of proteins can provide us a general picture of protein universe, assist protein design and analysis, and further our comprehension of the evolution of organisms. Here we carried out a study of the evolution of protein molecules by investigating homologous relationships among residue segments. The motive was to identify detailed topological features of homolo...