Estimating orientation factors in the FRET theory of fluorescent proteins: the TagRFP-KFP pair and beyond.

The orientation factor κ(2), one of the key parameters defining Förster resonance energy transfer efficiency, is determined by the transition dipole moment orientations of the donor and acceptor species. Using the results of quantum chemical and quantum mechanical/molecular mechanical calculations for the chromophore-containing pockets in selected colored proteins of the green fluorescent protein family, we derived transition dipole moments corresponding to the S0,min → S1 excitation for green fluorescent protein, red fluorescent protein (TagRFP), and kindling fluorescent protein, and the S1,min → S0 emission for TagRFP. These data allowed us to estimate κ(2) values for the TagRFP-linker-kindling fluorescent protein tetrameric complex required for constructing novel sensors.

Exploration of the zinc finger motif in controlling activity of matrix metalloproteinases.

Discovering ways to control the activity of matrix metalloproteinases (MMPs), zinc-dependent enzymes capable of degrading extracellular matrix proteins, is an important field of cancer research. We report here a novel strategy for assembling MMP inhibitors on the basis of oligopeptide ligands by exploring the pattern known as the zinc finger motif. Advanced molecular modeling tools were used to characterize the structural binding motifs of experimentally tested MMP inhibitors, as well as those of newly proposed peptidomimetics, in their zinc-containing active sites.

Expression of XBP1 in lymphocytes of the small intestine in rats under chronic social stress and modulation of intestinal microflora composition.

The present study was conducted to investigate of the influence of chronic social stress and modulation of the composition of intestinal microflora on the distribution of Xbp(1+)-lymphocytes in the gut-associated lymphoid tissue of ileum of the rats. Structure of population of Xbp(1+)-cells has been studied by the analysis of serial histological sections using the method of indirect immunofluorescence with monoclonal antibodies to Xbp1 of rat. Chronic social stress development is accompanied with the reduction of total number of Xbp(1+)-lymphocytes in lymphoid structures of ileum (31% -3 fold reduction, p < 0.

Multiphoton photochemistry of red fluorescent proteins in solution and live cells.

Genetically encoded fluorescent proteins (FPs), and biosensors based on them, provide new insights into how living cells and tissues function. Ultimately, the goal of the bioimaging community is to use these probes deep in tissues and even in entire organisms, and this will require two-photon laser scanning microscopy (TPLSM), with its greater tissue penetration, lower autofluorescence background, and minimum photodamage in the out-of-focus volume. However, the extremely high instantaneous light intensities of femtosecond pulses in the focal volume dramatically increase the probability of further stepwise resonant photon absorption, leading to highly excited, ionizable and reactive states, often resulting in fast bleaching of fluorescent proteins in TPLSM.

Study of expression of TLR2, TLR4 and transckription factor NF-kB structures of galt of rats in the conditions of the chronic social stress and modulation of structure of intestinal microflora.

The present study was conducted to investigate of the influence of chronic social stress (CSS) and modulation of the composition of intestinal microflora on the distribution of TLR2+-, TLR4+- and Nf-kB+-cells in the GALT of ileum of the rats. Researchers have been conducted on 84 rats (female) of Wistar line, which were divided on 7 experimental groups: control rats (group 1); rats, which were modeled CSS1 by means of three weeks social isolation and prolong psychoemotional influence (group2); rats, which having CSS 2 modeling by means of keeping animals in over populated cages with every day change of grouping (group 3); rats with CSS1 and CSS2, which were made the modeling of intestinal microflora by means of administrations of aminoglycosed antibiotic kanamycin (group 4 and 5, accordingly); rats with CSS1 and CSS2, which were made the modeling of intestinal microflora by means of everyday administrations of lactobacterine (groups 6 and 7, accordingly). Structure of population of TLR2+-, TLR4+- and Nf-kB+-cells has been studied by the analysis of serial histological sections using the method of direct and indirect immunofluorescense with monoclonal antibodies to TLR2, TLR4 and Nf-kB.