A fresh look at the Ramachandran plot and the occurrence of standard structures in proteins.

Conformational analysis of N- and C-terminally protected tripeptide model glycyl-isoleucine-glycyl: An ab initio and DFT study

An ab initio and density functional theory (DFT) study about conformational analysis of tripeptide model HCO−GLY−L−ILE−GLY−NH2 is presented. The tripeptide was scanned about initial, central, and final residues, separately while for every scanning procedure the two other residues had been kept in the β conformation and side chain (SC) dihedral angles were maintained on the gauche− (g‾) state (χ...

Critique of Research Book (Art)/ Structure or Text: A Look at the Art of Plot Forming, Shaapur Azimi

بررسی تمایل مجاورت اسیدهای آمینه با یکدیگر در مارپیچهای آلفا

In order to study the tendency of amino acid neighbors in helical structures, proteins with known structures were carefully analyzed. The studied helical positions: N , Ncap, N1, N2, N3, N4, M, C4, C3, C2, C1, Ccap, C and their doublet counterparts: N Ncap, NcapN1, N1N2, N2N3, N3N4, M1M2, M2M3, C4C3, C3C2, C2C1, C1Ccap, CcapC were carefully analyzed. The propensity for all amino acids i...

The Ramachandran Number: An Order Parameter for Protein Geometry

Three-dimensional protein structures usually contain regions of local order, called secondary structure, such as α-helices and β-sheets. Secondary structure is characterized by the local rotational state of the protein backbone, quantified by two dihedral angles called ϕ and ψ. Particular types of secondary structure can generally be described by a single (diffuse) location on a two-dimensional...

Context Recognition of the Tunisian Revolution Formation: in Dignity Search

The public considers sociopolitical revolutions and movements as phenomena that occur suddenly and unpredictably. Still, these phenomena carry historical content and stem from sophisticated sociopolitical, cultural, and economic factors in the view of political scientists. Such a view provides the context in which sociopolitical revolutions and movements are analyzed, not in a single cause, but...