Copper(II) complexes [Cu(l-arg)2](NO3)2 (1) and [Cu(l-arg)(B)Cl]Cl (2−5), where B is a heterocyclic base, namely, 2,2′-bipyridine (bpy, 2), 1,10-phenanthroline (phen, 3), dipyrido[3,2-d:2′,3′-f]quinoxaline (dpq, 4), dipyrido[3,2-a:2′,3′-c]phenazine (dppz, 5), are prepared their DNA binding photoinduced cleavage activity studied. Ternary complex 3, structurally characterized using X-ray crystallography, shows square-pyramidal (4 + 1) coordination geometry in which the N,O-donor l-arginine...

The self-assembly of a dehydrophenylalanine containing dipeptide (see figure), yielding highly ordered nanotubular structures, is discussed. tubes are longer and thinner than previously reported peptide-based tubular structures; they stable to boiling-water temperatures, different pH conditions, nonspecific protease (Proteinase K). Supporting information for this article available on the WWW under http://www.wiley-vch.de/contents/jc_2089/2007/c1774_s.pdf or from author. Please note:...

Abstract A comprehensive database analysis of CH…O hydrogen bonds in 3124 α‐helices and their corresponding helix termini has been carried out from a nonredundant data set high‐resolution globular protein structures resolved at better than 2.0 Å order to investigate role the helix, important secondary structural element. The possible occurrence 5 → 1 bond between i th residue CH group ( − 4)th CO with C…O ≤ 3.8 is studied, considering as potential donors main‐chain Cα side‐chain carbon...

Crystallographic insight-guided and bio-inspired molecular nanoarchitectonics of an n-type organic semiconductor is described to understand the structure–property correlation, for modulation functional properties.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDesign of a helical motif using .alpha.,.beta.-dehydrophenylalanine residues: crystal structure Boc-Val-.DELTA.Phe-Phe-Ala-Phe-.DELTA.Phe-Val-.DELTA.PHe-Gly-OCH3, 310-helical nonapeptideK. R. Rajashankar, S. Ramakumar, and V. ChauhanCite this: J. Am. Chem. Soc. 1992, 114, 23, 9225–9226Publication Date (Print):November 1, 1992Publication History Published online1 May 2002Published inissue 1 November...

Abrin and agglutinin-I from the seeds of Abrus precatorius are type II ribosome-inactivating proteins that inhibit protein synthesis in eukaryotic cells. The two toxins share a high degree sequence similarity; however, is weaker its activity. We compared kinetics inhibition by abrin different cell lines found approximately 200-2000-fold higher concentration needed for same inhibition. Like abrin, also induced apoptosis cells triggering intrinsic mitochondrial pathway, although at...

Binuclear copper(II) complexes [{(phen)CuII}2(μ-dtdp)2] (1), [{(dpq)CuII}2(μ-dtdp)2] (2), [{(phen)CuII}2(μ-az)2] (3), and [{(dpq)CuII}2(μ-az)2] (4) a zinc(II) complex [{(phen)ZnII}2(μ-dtdp)2] (5), having 3,3′-dithiodipropionic acid (H2dtdp), azelaic (nonanedioic acid), 1,10-phenanthroline (phen), dipyrido[3,2-d:2′,3′-f]quinoxaline (dpq), were prepared characterized by physicochemical methods. Complex 1 has been structurally X-ray crystallography. The have each metal center bound to chelating...

Ternary copper(II) complexes [Cu(L-trp)(B)(H2O)](NO3) (1–3) and [Cu(L-phe)(B)(H2O)](NO3) (4–6) of L-tryptophan (L-trp) L-phenylalanine (L-phe) having phenanthroline bases (B), viz. 1,10-phenanthroline (phen, 1 4), dipyrido[3,2-d:2′,3′-f]quinoxaline (dpq, 2 5) dipyrido[3,2-a:2′,3′-c]phenazine (dppz, 3 6), were prepared characterized by physico-chemical techniques. Complexes 6 structurally X-ray crystallography show the presence a square pyramidal (4 + 1) CuN3O2 coordination geometry in which...

hIAPP fibrillization implicated in Type 2 diabetes pathology involves formation of oligomers toxic to insulin producing pancreatic β-cells. We report design, synthesis, 3D structure and functional characterization dehydrophenylalanine (ΔF) containing peptides which inhibit fibrillization. The inhibitor protects β-cells from induced toxicity.

Biomimetic molecular organization of naphthalene diimide in the solid state: tunable (chiro-) optical, viscoelastic and nanoscale properties.

Crystal structures are known for several glycosyl hydrolase family 10 (GH10) xylanases. However, none of them is from an alkalophilic organism that can grow in alkaline conditions. We have determined the crystal at 2.2 Angstroms a GH10 extracellular endoxylanase (BSX) Bacillus sp. NG-27, native and complex enzyme with xylosaccharides. The industrially important optimally active stable 343 K pH 8.4. Comparison structure BSX those other thermostable xylanases acidic or close to neutral showed...

Background Stabilization strategies adopted by proteins under extreme conditions are very complex and involve various kinds of interactions. Recent studies have shown that a large proportion their N- C-terminal elements in close contact suggested they play role protein folding stability. However, the biological significance this remains elusive. Methodology In present study, we investigate residue interaction using family 10 xylanase (BSX) with TIM-barrel structure shows stability high...

Peptide based self assembled nanostructures have attracted growing interest in recent years due to their numerous potential applications particularly biomedical sciences. Di-peptide Phe-Phe was shown previously self-assemble into nanotube like structures. In this work, we studied the affect of peptide backbone length and conformational flexibility on assembly process by using two dipeptides (βPhe-Phe βPhe-ΔPhe): one containing a flexible βPhe amino acid, other both as well constraining ΔPhe...

Abstract The i + 5 → hydrogen bonded turn conformation (7r‐turn) with the fifth residue adopting α L is frequently found at C‐terminus of helices in proteins and hence speculated to be a “helix termination signal.” An analysis occurrence any general position (not specifically helix C‐terminus), using coordinates 228 protein crystal structures determined by X‐ray crystallography better than 2.5 Å resolution reported this paper. Of 486 detected π‐turn conformations, 367 have ( 4)th...

Design of helical super secondary structural motifs is expected to provide important scaffolds incorporate functional sites, thus allowing the engineering novel miniproteins with function. An α,β-dehydrophenylalanine containing 21-residue apolar peptide was designed mimic hairpin motif by using a simple geometrical design strategy. The synthetic folds into desired structure as assessed crystallographically at 1.0-Å resolution. two helices helical-hairpin motif, connected flexible (Gly) 4...

The solution and solid structure of Boc-l-Val-ΔPhe-ΔPhe-ΔPhe-l-Val-OMe, containing three consecutive ΔPhe residues, have been determined by X-ray diffraction, nuclear magnetic resonance, circular dichroism methods. crystals grown from aqueous methanol are orthorhombic, space group P212121, a = 11.624(2), b 17.248(2), c 21.532 Å, V 4216 (1) Å3, Z 4. In the state, peptide exhibits left-handed 310-helical conformation, in spite presence two l-Val residues. NMR CD studies different solvents also...

Pancreatic phospholipase A2 (PLA2) shows a strong preference for the binding to anionic interface and consequent allosteric activation. In this paper, we show that virtually all is mediated through 3 (Lys-53, -56, -120) of 12 cationic residues bovine pancreatic PLA2. The lysine-to-methionine substitution enhances enzyme zwitterionic interface, K53,56,120M triple mutant at comparable wild type (WT) interface. isomorphous crystal structure, backbone folding K53,56M K120,121A WT are identical,...

Copper(II) bis-arginate [Cu(l-arg)2](NO3)2 (1) and [Cu(l-arg)(phen)Cl]Cl (2) as mimics of the minor-groove-binding natural antibiotic netropsin show preferential binding to AT-rich region double-stranded DNA. The complexes with a d-d band near 600 nm display oxidative DNA cleavage activity on photoirradiation at UV-A light 365 red 647.1 (Ar-Kr laser) in metal-assisted photoexcitation process forming singlet oxygen (1O2) species type-2 pathway.

Abstract The nicotinic Acetylcholine Receptor (nAChR) is the major class of neurotransmitter receptors that involved in many neurodegenerative conditions such as schizophrenia, Alzheimer's and Parkinson's diseases. N-terminal region or Ligand Binding Domain (LBD) nAChR located at pre- post-synaptic nervous system, which mediates synaptic transmission. acts drug target for agonist competitive antagonist molecules modulate signal transmission nerve terminals. Based on Protein (AChBP) from...