The Analysis of Cu(II)/Zn(II) Cyclopeptide System as Potential Cu,ZnSOD Mimic Center.

In this paper are presented the features of copper (II) and zinc (II) heteronuclear complexes of the cyclic peptide-c(HKHGPG). The coordination properties of ligand were studied by potentiometric, UV-Vis and CD spectroscopic methods. These experiments were carried out in aqueous solutions at 298 K depending on pH.

The coordination abilities of the multiHis-cyclopeptide with two metal-binding centers--potentiometric and spectroscopic investigation.

In this paper we present the formation of mono- and binuclear complexes by the octapeptide (c(HKHPHKHP)) with copper(II) ions. The ligand was synthesized manually by the solid-phase method. Its characteristic cyclic structure significantly influences the coordination abilities.

Molecular determinants of the interaction between human high molecular weight kininogen and Candida albicans cell wall: Identification of kininogen-binding proteins on fungal cell wall and mapping the cell wall-binding regions on kininogen molecule.

An excessive production of vasoactive and proinflammatory bradykinin-related peptides, the kinins, is often involved in the human host defense against microbial infections. Recent studies have shown that a major fungal pathogen to humans, Candida albicans, can bind the proteinaceous kinin precursor, the high molecular weight kininogen (HK) and trigger the kinin-forming cascade on the cell surface. In this work, we preliminarily characterized a molecular mechanism underlying the HK adhesion to the fungal surface by (i) identification of major kininogen-binding constituents on the candidial cell wall and (ii) mapping the cell wall-binding regions on HK molecule.

Colorimetric evaluation of the time-killing assay for Citropin 1.1, lipopeptide Palm-KK-NH2, and Temporin A.

Nowadays, there are a number of colorimetric techniques available for the determination of a time killing assay in a manner much easier and faster than those previously more commonly used, which were much more time-consuming and laborious colony counting procedures. Here, an attempt has been made to test the antimicrobial peptides of Citropin 1.1, Palm-KK-NH2, and Temporin A on a reference strain of Staphylococcus aureus using resazurin as the cell viability reagent.

The -Cys-Cys- motif in Helicobacter pylori's Hpn and HspA proteins is an essential anchoring site for metal ions.

The Hpn and HspA proteins from H. pylori are significant for nickel homeostasis and protect the cells from higher concentrations of external metal ions. Both proteins have a unique histidine- and cysteine-rich domain at the C terminus.

Camelina sativa cake improved unsaturated fatty acids in ewe's milk.

Background: Camelina sativa cake (CSC), a rich source of unsaturated fatty acids, in the case of ruminants, may improve the energy value of a diet and also increase the unsaturated fatty acid content in milk. Effects of basal diet (control), basal diet plus 30 g kg(-1) of CSC in dietary dry matter (DM), basal diet plus 60 g kg(-1) of CSC in dietary dry matter on milk production and the fatty acid composition of ewe's milk with particular emphasis on the monoenes and conjugated isomers of linoleic acid content were examined.

Results: Elevated concentration of total monounsaturated fatty acids, the effect of an increase in monounsaturated fatty acids in the trans configuration, as well as the increased content of total polyunsaturated fatty acids, resulted from CSC supplementation.

Synthesis, biological activity and solution structure of new analogues of the antimicrobial Gramicidin S.

Gramicidin S (GS) is a cyclo-decapeptide antibiotic isolated from Bacillus brevis. The structural studies have shown that GS forms a two-stranded antiparallel β-sheet imposed by two II' β-turns. Despite its wide Gram+ and Gram- antimicrobial spectrum, GS is useless in therapy because of its high hemotoxicity in humans.

The cyclopeptides with the multi-His motif as ligands for copper(II).

The coordination properties of cyclic octapeptides with multi-His motif: c(His-Gly-His-Xaa-His-Gly-His-Xaa) where Xaa = Asp or Lys, were investigated. The binding abilities of this peptides towards Cu(II) ions were studied by using different analytic methods as: potentiometry, spectroscopy and mass spectrometry. The obtained results show that the studied peptides in physiological related pH prefer formation of the species with the {4N(Im)} binding mode.

Cu2+ and Ni2+ interactions with N-terminal fragments of Hpn and Hpn-like proteins from Helicobacter pylori: unusual impact of poly-Gln sequence on the complex stability.

The N-terminal protected and unprotected peptides MAHHEEQHG-NH(2), Ac-MAHHEEQHG-NH(2) from Hpn (Helicobacter histidine-rich protein) and MAHHEQQQQQQA-NH(2), Ac-MAHHEQQQQQQA-NH(2) from Hpn-like protein, respectively, were synthesized and their interactions with Cu(2+) and Ni(2+) ions were studied by potentiometric, UV-visible, CD, and EPR techniques. The studies have shown that because of their albumin-like sequence, unprotected peptides are very effective chelating agents for both studied metals. The presence of the hexa-glutamine sequence has very distinct impact on the stability of the complexes formed even if direct interactions with metal ions were not found.