DNA-hydrolyzing Ab: is catalytic activity a clue for physiological significance?

Ab with DNA-hydrolyzing properties were described in autoimmune pathologies, such as SLE and RA, and in other autoimmune diseases, including chronic lymphocytic leukemia, AIDS, and others. The disease-associated DNA-binding AAb penetrate cell membrane and enter the nucleus. Intracellular entry of anti-DNA was linked to cellular damage and apo.

N-terminal amphipathic helix as a trigger of hemolytic activity in antimicrobial peptides: a case study in latarcins.

In silico structural analyses of sets of alpha-helical antimicrobial peptides (AMPs) are performed. Differences between hemolytic and non-hemolytic AMPs are revealed in organization of their N-terminal region. A parameter related to hydrophobicity of the N-terminal part is proposed as a measure of the peptide propensity to exhibit hemolytic and other unwanted cytotoxic activities.

Cytostatic activity of peptide extracts of medicinal plants on transformed A549, H1299, and HeLa Cells.

Biological activity of peptide extracts of medicinal plants was studied on transformed non-small-cell lung carcinoma A549 cells, lung cancer H1299 cells, and cervical cancer HeLa cells at various cell densities. Cell survival and proliferation were evaluated 72 h after treatment with extracts in concentrations of 0.05, 0.

Effect of delta-sleep-inducing peptide on expression of heat shock protein 70 kDa in K562 cells.

For evaluation of the stress-protective influence of delta-sleep inducing peptide we studied its effects on the system of heat-shock proteins in immune cells using the method of flow cytometry. The peptide affected the expression of heat-shock protein 70 kDa in cultured human myeloleukemia K562 cells. Delta-sleep-inducing peptide reduces accumulation of intracellular heat shock proteins 70 kDa in cells cultured under conditions of high density.

Bilateral occlusion of carotid artery in awake hypertensive rats (SHR-SP) as a model of global cerebral ischemia.

Bilateral occlusion of carotid arteries in awake hypertensive rats (SHR-SP) was used as a model of global brain ischemia (duration of occlusion--until appearance of seizures). In normotensive rats (WKY), no seizures developed over 60 min. We revealed swelling of mitochondria in dendrites of hippocampal CA1 pyramidal cells, which was more pronounced in SHP-SP than in WKY rats.

Fluorescent immunolabeling of cancer cells by quantum dots and antibody scFv fragment.

Semiconductor quantum dots (QDs) coupled with cancer-specific targeting ligands are new promising agents for fluorescent visualization of cancer cells. Human epidermal growth factor receptor 2/neu (HER2/neu), overexpressed on the surface of many cancer cells, is an important target for cancer diagnostics. Antibody scFv fragments as a targeting agent for direct delivery of fluorophores offer significant advantages over full-size antibodies due to their small size, lower cross-reactivity, and immunogenicity.

Substrate recognition of anthrax lethal factor examined by combinatorial and pre-steady-state kinetic approaches.

Lethal factor (LF), a zinc-dependent protease of high specificity produced by Bacillus anthracis, is the effector component of the binary toxin that causes death in anthrax. New therapeutics targeting the toxin are required to reduce systemic anthrax-related fatalities. In particular, new insights into the LF catalytic mechanism will be useful for the development of LF inhibitors.

PLATINUM: a web tool for analysis of hydrophobic/hydrophilic organization of biomolecular complexes.

Unlabelled: The PLATINUM (Protein-Ligand ATtractions Investigation NUMerically) web service is designed for analysis and visualization of hydrophobic/hydrophilic properties of biomolecules supplied as 3D-structures. Furthermore, PLATINUM provides a number of tools for quantitative characterization of the hydrophobic/hydrophilic match in biomolecular complexes e.g.

Evaluation of antitumor activity of peptide extracts from medicinal plants on the model of transplanted breast cancer in CBRB-Rb(8.17)1Iem mice.

We studied antitumor effects of peptide extracts from plants on slowly growing mammary adenocarcinoma in CBRB-Rb(8.17)1Iem mice used as a model of breast cancer in humans. The antitumor effect of a single injection of the test peptides was evaluated by the delay of the appearance and growth of palpable breast cancer in mice over 4 weeks.

Epitope mapping of human Fas using peptide phage display.

Sandwich EIA for measurement of soluble Fas was developed on the basis of SA-7 and SA-8 monoclonal antibodies to full-length human Fas. The threshold sensitivity of the test system is 0.3 ng/ml.

Changes in the status of nucleolus during long-term culturing of human HeLa cells.

Changes in the immunocytochemical status of the nucleoli during long-term (6-8 months) in vitro culturing of HeLa (carcinoma of the cervix uteri) cells were described using new A3 monoclonal antibodies selectively reacting with human cell nucleoli. The appearance of cells with abnormal location of A3 antigen was paralleled by a significant increase of culture sensitivity to some external factors (protein synthesis inhibition and oxidative stress). The data indicate that location of one of the nucleolar antigens is an indicator of the qualitative status of HeLa cells in the culture.

Bacterial production of latarcin 2a, a potent antimicrobial peptide from spider venom.

Natural venoms are promising sources of candidate therapeutics including antibiotics. A recently described potent antimicrobial peptide latarcin 2a (Ltc 2a) from Lachesana tarabaevi spider venom shows a broad-spectrum antibacterial activity. This peptide consists of 26 amino acid residues and therefore its production using chemical synthesis, although trivial, is costly.

Mechanisms of defense formation against meningococcal infection in mice immunized with synthetic peptides.

Immunization of mice with synthetic peptide fragments of conservative sites of meningococcal outer membrane proteins led to defense formation against infection with virulent serogroup A and B Meningococci. The role of cellular immunity in the formation of defense against meningococcal infection after immunization with the peptides and the possibility of stimulating lymphocyte population with these peptides were demonstrated.

Glucosaminylmuramyl dipeptide potentiates the effects of tumor necrosis factor-alpha and cisplatin on transformed cells in vitro.

We studied the effect of combined treatment with cisplatin, glucosaminylmuramyl dipeptide, and TNF-alpha on viability of MCF-7, U-937, B16, and L-929 tumor cells, Ehrlich ascites carcinoma cells, and normal cells (human peripheral blood lymphocytes, peritoneal macrophages, and mouse bone marrow cells). Glucosaminylmuramyl dipeptide was nontoxic for normal and tumor cells, but promoted death of tumor cells after administration in combination with cisplatin and/or TNF-alpha. At the same time, glucosaminylmuramyl dipeptide did not modulate the cytotoxic effect of individual or combined treatment with cisplatin and TNF-alpha on normal cells.

The membrane-proximal fusion domain of HIV-1 GP41 reveals sequence-specific and fine-tuning mechanism of membrane binding.

The membrane interface-partitioning region preceding the transmembrane anchor of the human immunodeficiency virus type 1 (HIV-1) gp41 envelope protein is one of the sites responsible for virus binding to its host cell membrane and subsequent fusion events. Here, we used molecular modeling techniques to assess membrane interactions, structure, and hydrophobic properties of the fusion-active peptide representing this region, several of its homologs from different HIV-1 strains, as well as a peptide - defective gp41 phenotype - unable to mediate cell-cell fusion and virus entry. It is shown that the wild-type peptides bind to the water-membrane interface in alpha-helical conformation, while the mutant adopts partly destabilized helix-break-helix structure on the membrane surface.

Specificity of helix packing in transmembrane dimer of the cell death factor BNIP3: a molecular modeling study.

BNIP3 is a mitochondrial 19-kDa proapoptotic protein, a member of the Bcl-2 family. It has a single COOH-terminal transmembrane (TM) alpha-helical domain, which is required for membrane targeting, proapoptotic activity, hetero- and homo-dimerization in membrane. The role and the molecular details of association of TM helices of BNIP3 are yet to be established.

Docking of ATP to Ca-ATPase: considering protein domain motions.

Most standard molecular docking algorithms take into account only ligand flexibility, while numerous studies demonstrate that receptor flexibility may be also important. While some efficient methods have been proposed to take into account local flexibility of protein side chains, the influence of large-scale domain motions on the docking results still represents a challenge for computational methods. In this work we compared the results of ATP docking to different models of Ca-ATPase: crystallographic apo- and holo-forms of the enzyme as well as "flexible" target models generated via molecular dynamics (MD) simulations in water.

Antioxidant and neuroprotective properties of N-docosahexaenoyl dopamine.

N-Docosahexaenoyl dopamine exhibited antioxidant activity in the test with a stable oxygen radical galvinoxyl. This compound produced a dose-dependent protective effect on cultured granular cells from rat cerebellum under conditions of oxidative stress. N-Docosahexaenoyl dopamine decelerated the development of symptoms of Parkinson's disease in mice receiving neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine.

Hemodynamic effects of peptide fragments of differentiation factor HLDF.

Hemodynamic activity of peptides from differentiation factor HLDF (promyelocytic HL-60 line) was studied on WKY and SHR-SP rats. Intravenous infusion of the test peptides was accompanied by changes in blood pressure and heart rate, which depended on the structure of peptides and functional activity of the organism and differed in normotensive and hypertensive animals.

Molecular lipophilicity in protein modeling and drug design.

Hydrophobic interactions play a key role in the folding and maintenance of the 3-dimensional structure of proteins, as well as in the binding of ligands (e.g. drugs) to protein targets.

Complementarity of hydrophobic properties in ATP-protein binding: a new criterion to rank docking solutions.

ATP is an important substrate of numerous biochemical reactions in living cells. Molecular recognition of this ligand by proteins is very important for understanding enzymatic mechanisms. Considerable insight into the problem may be gained via molecular docking simulations.

Experimental model of hemorrhagic stroke: rabbit immunization with HL-60 promyelocytic cell differentiation factor.

Rabbits immunized with synthetic HLDF differentiation factor developed hemorrhagic stroke with thrombosis of small cerebral vessels and destruction of vascular endotheliocytes. The severity of stroke correlated with serum level of antibodies to differentiation factor. The role of different sites of HLDF molecule in the induction of clinical signs of hemorrhagic stroke was studied.

Association of transmembrane helices: what determines assembling of a dimer?

Self-association of two hydrophobic alpha-helices is studied via unrestrained Monte Carlo (MC) simulations in a hydrophobic slab described by an effective potential. The system under study represents two transmembrane (TM) segments of human glycophorin A (GpA), which form homo-dimers in membranes. The influence of TM electrostatic potential, thickness and hydrophobicity degree of lipid bilayer is investigated.

Induction of differentiation in leukemic cell strains with myelopeptide-4.

We studied the capacity of myelopeptide-4 (regulatory peptide of the bone marrow origin) to induce terminal differentiation of HL-60 and K-562 leukemic cells. Myelopeptide-4 increased the expression of CD14 and CD38 differentiation antigens on the surface of HL-60 cells and of CD44 antigen on K-562 cells, induced the appearance of mature monocyte/macrophages in HL-60 culture and hemoglobin-producing cells in K-562 cell culture, and stimulated phagocytic activity of THP-1 leukemic cells. Myelopeptide-4 is an endogenous factor of cell differentiation, a prospective agent for antileukemic therapy.

Genomic fingerprinting of Burkholderia pseudomallei and B. mallei pathogens with DNA array based on interspecies sequence differences obtained by subtractive hybridization.

The ability to rapidly and efficiently identify causative agents of dangerous human and animal diseases is a prerequisite to diagnosis, prophylaxis and therapy. Such identification systems can be developed based on DNA markers enabling differentiation between various bacterial strains. One source of these markers is genetic polymorphism.