in the present work, an extensive theoretical calculation study on histidine-histidine dipeptide in gas phase is done by using dft method with gaussian 98 program. through investigations on the molecular geometries of this molecule it is found that there is six rings in the molecules not two rings. the presence of four intramolecular hydrogen bonds is responsible for the formation of additional...

hydrogen bonding of dppe with water that surrounded of membrane, plays an important role in permeability ofmembrane that we were presented this matter with analysis of bond angles and torsion angles before and after ofadded water molecules.interaction with water molecules causes some changes in the geometry of dppe which were explained bythe contribution of zwitterionic form of dppe molecule, a...

the mathematical properties of nano molecules are an interesting branch of nanoscience forresearches nowadays. the periodic open single wall tubulene is one of the nano moleculeswhich is built up from two caps and a distancing nanotube/neck. we discuss how toautomatically construct the graph of this molecule and plot the graph by spring layoutalgorithm in graphviz and netwrokx packages. the sim...

within the past few years, neat scheme has been overturned by the discovery that rna can act as an enzyme. what does the starting finding of rna enzymes imply? thre first implication is that one can no longer assume a protein lies behind every catalytic activity of the cell. it now appears that several of the operations that tailor an ran molecule into its final form are at least in part cataly...