Kringle 4 from human plasminogen: a proton magnetic resonance study via two-dimensional photochemically induced dynamic nuclear polarization spectroscopy

Two-dimensional (2D) proton magnetic resonance techniques used in conjunction with laser photochemically induced dynamic nuclear polarization (photo-CIDNP) spectroscopy have been applied to studying the kringle 4 domain from human plasminogen at 360 MHz. Out of 11 potential CIDNP-sensitive aromatic side chains, only 5 (His3, Tyr41, Tyr50, Trp72, and Tyr74) appear to be accessible to 3-(carboxymethyl)lumiflavin, the dye used to photogenerate spin polarization. Of these, Trp72 and Tyr74 are known to be at, or near, the lysine-binding site. The spin-spin scalar (J) and phase-sensitive dipolar (Overhauser) connectivities in the 2D experiments yield absolute assignments for the aromatic signals stemming from the exposed tyrosyl and tryptophanyl rings. Moreover, a number of side-chain H beta resonances can be identified and assigned to specific types of aromatic amino acid residues.     

Solution conformation of tuftsin.

Tuftsin, a natural linear tetrapeptide (Thr-Lys-Pro-Arg) of potential antitumor activity, has been studied in DMSO-d6 solution by 2D NMR spectroscopy. 1H and 13C spectra show the presence of two families of conformations characterized by a trans or cis Lys-Pro bond, respectively. The family of conformers containing the cis peptide bond is a mixture of extended structures as expected for a short linear peptide. On the contrary, the trans isomer appears to be a rigid, folded conformer, as indicated by crucial NOEs and by the exceptionally low temperature coefficient of Arg NH. Analysis of the solution data by means of energy calculations leads to a unique structure, characterized by a Lys-Pro inverse gamma-turn.     

Circular dichroism and proteolysis of human beta-endorphin in surfactant and lipid solutions

The influence of micelles of sodium dodecyl sulfate, cetyltrimethylammonium bromide, lysophosphatidylcholine and dodecylphosphorylcholine on the content and stability of the ordered structure of human beta-endorphin and its 12-26 fragment has been investigated. The structure was determined by far-ultraviolet circular dichroism and the stability by the resistance of the polypeptide to proteolysis with trypsin and chymotrypsin, monitored by HPLC. The alpha-helix inducing effects of the amphipathic compounds were in the order anionic greater than zwitterionic greater than cationic. The protection against proteolysis was very marked, especially for trypsin, and it was proportional to the alpha-helix inducing potential of amphipathic compounds. However, the lower resistance to proteolysis of the highly structured 12-26 fragment suggests that factors other than secondary structure may be responsible for the resistance to proteolysis.     

Distance evaluation via heteronuclear SQC-NOESY experiments

Summary A method for the quantitative determination of interproton distances from¹H NOE relayed heteronuclear correlation is presented. Model compounds are investigated. Accurate distances are obtained if all the factors affecting such distance measurements, such as the local mobility and the presence of strong coupling in heteronuclear systems, are properly taken into account.     

Identification of gene expression profiles in myocardial infarction: a systematic review and meta-analysis

Background

Myocardial infarction (MI) is a multifactorial disease with complex pathogenesis, mainly the result of the interplay of genetic and environmental risk factors. The regulation of thrombosis, inflammation and cholesterol and lipid metabolism are the main factors that have been proposed thus far to be involved in the pathogenesis of MI. Traditional risk-estimation tools depend largely on conventional risk factors but there is a need for identification of novel biochemical and genetic markers. The aim of the study is to identify differentially expressed genes that are consistently associated with the incidence myocardial infarction (MI), which could be potentially incorporated into the traditional cardiovascular diseases risk factors models.

Methods

The biomedical literature and gene expression databases, PubMed and GEO, respectively, were searched following the PRISMA guidelines. The key inclusion criteria were gene expression data derived from case-control studies on MI patients from blood samples. Gene expression datasets regarding the effect of medicinal drugs on MI were excluded. The t-test was applied to gene expression data from case-control studies in MI patients.

Results

A total of 162 articles and 174 gene expression datasets were retrieved. Of those a total of 4 gene expression datasets met the inclusion criteria, which contained data on 31,180 loci in 93 MI patients and 89 healthy individuals. Collectively, 626 differentially expressed genes were detected in MI patients as compared to non-affected individuals at an FDR q-value?=?0.01. Of those, 88 genes/gene products were interconnected in an interaction network. Totally, 15 genes were identified as hubs of the network.

Conclusions

Functional enrichment analyses revealed that the DEGs and that they are mainly involved in inflammatory/wound healing, RNA processing/transport mechanisms and a yet not fully characterized pathway implicated in RNA transport and nuclear pore proteins. The overlap between the DEGs identified in this study and the genes identified through genetic-association studies is minimal. These data could be useful in future studies on the molecular mechanisms of MI as well as diagnostic and prognostic markers.

     

Occurence of grapevine chrome mosaic nepovirus in Austria

A virus recovered by inoculation of sap from Austrian vines with yellow mosaic symptoms was compared with, and found virtually indistinguishable from, an authentic Hungarian isolate of grapevine chrome mosaic nepovirus. This seems to be the first record of the virus in Austria.     

Microbial cyclophilins: specialized functions in virulence and beyond

Cyclophilins belong to the superfamily of peptidyl-prolyl cis/trans isomerases (PPIases, EC: 5.2.1.8), the enzymes that catalyze the cis/trans isomerization of peptidyl-prolyl peptide bonds in unfolded and partially folded polypeptide chains and native state proteins. Cyclophilins have been extensively studied, since they are involved in multiple cellular processes related to human pathologies, such as neurodegenerative disorders, infectious diseases, and cancer. However, the presence of cyclophilins in all domains of life indicates a broader biological importance. In this mini-review, we summarize current advances in the study of microbial cyclophilins. Apart from their anticipated role in protein folding and chaperoning, cyclophilins are involved in several other biological processes, such as cellular signal transduction, adaptation to stress, control of pathogens virulence, and modulation of host immune response. Since many existing family members do not have well-defined functions and novel ones are being characterized, the requirement for further studies on their biological role and molecular mechanism of action is apparent.     

Fibroblast growth factor 2‐antagonist activity of a long‐pentraxin 3‐derived anti‐angiogenic pentapeptide

Fibroblast growth factor‐2 (FGF2) plays a major role in angiogenesis. The pattern recognition receptor long‐pentraxin 3 (PTX3) inhibits the angiogenic activity of FGF2. To identify novel FGF2‐antagonistic peptide(s), four acetylated (Ac) synthetic peptides overlapping the FGF2‐binding region PTX3‐(97–110) were assessed for their FGF2‐binding capacity. Among them, the shortest pentapeptide Ac‐ARPCA‐NH₂ (PTX3‐[100–104]) inhibits the interaction of FGF2 with PTX3 immobilized to a BIAcore sensorchip and suppresses FGF2‐dependent proliferation in endothelial cells, without affecting the activity of unrelated mitogens. Also, Ac‐ARPCA‐NH₂ inhibits angiogenesis triggered by FGF2 or by tumorigenic FGF2‐overexpressing murine endothelial cells in chick and zebrafish embryos, respectively. Accordingly, the peptide hampers the binding of FGF2 to Chinese Hamster ovary cells overexpressing the tyrosine‐kinase FGF receptor‐1 (FGFR1) and to recombinant FGFR1 immobilized to a BIAcore sensorchip without affecting heparin interaction. In all the assays the mutated Ac‐ARPS A‐NH₂ peptide was ineffective. In keeping with the observation that hydrophobic interactions dominate the interface between FGF2 and the FGF‐binding domain of the Ig‐like loop D2 of FGFR1, amino acid substitutions in Ac‐ARPCA‐NH₂ and saturation transfer difference‐nuclear magnetic resonance analysis of its mode of interaction with FGF2 implicate the hydrophobic methyl groups of the pentapeptide in FGF2 binding. These results will provide the basis for the design of novel PTX3‐derived anti‐angiogenic FGF2 antagonists.     

Characterization of nitrogen-fixing bacteria isolated from field-grown barley,oat, and wheat

Diazotrophic bacteria were isolated from the rhizosphere of field-grown Triticum aestivum, Hordeum vulgare, and Avena sativa grown in various regions of Greece. One isolate, with the highest nitrogen-fixation ability from each of the eleven rhizospheres, was selected for further characterisation. Diazotrophic strains were assessed for plant-growth-promoting traits such as indoleacetic acid production and phosphate solubilisation. The phylogenies of 16S rRNA gene of the selected isolates were compared with those based on dnaK and nifH genes. The constructed trees indicated that the isolates were members of the species Azospirillum brasilense, Azospirillum zeae, and Pseudomonas stutzeri. Furthermore, the ipdC gene was detected in all A. brasilence and one A. zeae isolates. The work presented here provides the first molecular genetic evidence for the presence of culturable nitrogen-fixing P. stutzeri and A. zeae associated with field-grown A. sativa and H. vulgare in Greece.     

Melissopalynological analysis of royal jelly from Greece

Microscopic analysis of 82 royal jelly samples obtained from several locations in Greece was carried out in order to study the pollen spectrum of Greek royal jelly. The analysis recorded over 60 taxa. The abundance of each pollen type varied among the areas and the samples. The most frequent pollen types found in the samples were Brassicaceae, Olea europaea, Eucalyptus, Trifolium, Rubus, Carduus-type, Hypericum, Daucus-type and Cistus. The majority of the pollen types found in the royal jelly samples were also found at the pollen flora around the apiaries.