Cytotoxic effects of two extracts from garlic (Allium sativum L.) cultivars on the human squamous carcinoma cell line SCC-15

Garlic (Allium sativum L., Alliaceae) has acquired a reputation as a therapeutic agent and herbal remedy to prevent and treat several pathologies. The aim of the present study was to determine the effect of two Allium sativum L. cultivars, Harna? and Morado, on reactive oxygen species (ROS) production, viability and apoptotic process in human squamous carcinoma cell line SCC-15. The experiments were conducted on SCC-15 cell line exposed to increasing concentrations of garlic extracts of 0.062, 0.125, 0.250, 0.500 and 1.000 mg/mL. After the experiments, ROS formation, caspase-3 activity and neutral red uptake were measured in the cells, and in a collected medium lactate dehydrogenase (LDH) release was measured. The Spanish cultivar Morado has demonstrated higher potential to stimulate ROS production in SCC-15 cells after a short time period (6 h) than the Polish cultivar Harna?. However, the Polish cultivar Harna? manifested more prolonged potential to stimulate ROS production in SCC-15 cells. Both studied garlic extracts induced cytotoxicity on SCC-15 cell line which was probably ROS-dependent. We also determined that in SCC-15 cells high concentrations of studied extracts did not cause activation of caspase-3 which suggested caspase-independent or necrotic cell death.     

The crystal structure of the AF2331 protein from Archaeoglobus fulgidus DSM 4304 forms an unusual interdigitated dimer with a new type of α + β fold

The structure of AF2331, a 11‐kDa orphan protein of unknown function from Archaeoglobus fulgidus, was solved by Se‐Met MAD to 2.4 Å resolution. The structure consists of an α + β fold formed by an unusual homodimer, where the two core β‐sheets are interdigitated, containing strands alternating from both subunits. The decrease in solvent‐accessible surface area upon dimerization is unusually large (3960 Ų) for a protein of its size. The percentage of the total surface area buried in the interface (41.1%) is one of the largest observed in a nonredundant set of homodimers in the PDB and is above the mean for nearly all other types of homo‐oligomers. AF2331 has no sequence homologs, and no structure similar to AF2331 could be found in the PDB using the CE, TM‐align, DALI, or SSM packages. The protein has been identified in Pfam 23.0 as the archetype of a new superfamily and is topologically dissimilar to all other proteins with the “3‐Layer (BBA) Sandwich” fold in CATH. Therefore, we propose that AF2331 forms a novel α + β fold. AF2331 contains multiple negatively charged surface clusters and is located on the same operon as the basic protein AF2330. We hypothesize that AF2331 and AF2330 may form a charge‐stabilized complex in vivo, though the role of the negatively charged surface clusters is not clear.     

Protein-cationic detergent interaction. Fourier transform infrared and laser Raman spectroscopic studies on the interaction between proteins and dodecylpyridinium bromide.

Fourier transform infrared and laser Raman spectroscopies were used to study the effects of dodecylpyridinium bromide on the conformation of haemoglobin, myoglobin, bovine serum albumin, ribonuclease, ovalbumin, lysozyme, trypsin and beta-lactoglobulin in aqueous solution. Addition of the cationic detergent caused a decrease in alpha-helix conformation in highly helical proteins. At low detergent concentrations stabilization of beta-sheet conformation was observed.     

Distinct Protein Classes in Human Red Cell Proteome Revealed by Similarity of Phylogenetic Profiles

The minimal set of proteins necessary to maintain a vertebrate cell forms an interesting core of cellular machinery. The known proteome of human red blood cell consists of about 1400 proteins. We treated this protein complement of one of the simplest human cells as a model and asked the questions on its function and origins. The proteome was mapped onto phylogenetic profiles, i.e. vectors of species possessing homologues of human proteins. A novel clustering approach was devised, utilising similarity in the phylogenetic spread of homologues as distance measure. The clustering based on phylogenetic profiles yielded several distinct protein classes differing in phylogenetic taxonomic spread, presumed evolutionary history and functional properties. Notably, small clusters of proteins common to vertebrates or Metazoa and other multicellular eukaryotes involve biological functions specific to multicellular organisms, such as apoptosis or cell-cell signaling, respectively. Also, a eukaryote-specific cluster is identified, featuring GTP-ase signalling and ubiquitination. Another cluster, made up of proteins found in most organisms, including bacteria and archaea, involves basic molecular functions such as oxidation-reduction and glycolysis. Approximately one third of erythrocyte proteins do not fall in any of the clusters, reflecting the complexity of protein evolution in comparison to our simple model. Basically, the clustering obtained divides the proteome into old and new parts, the former originating from bacterial ancestors, the latter from inventions within multicellular eukaryotes. Thus, the model human cell proteome appears to be made up of protein sets distinct in their history and biological roles. The current work shows that phylogenetic profiles concept allows protein clustering in a way relevant both to biological function and evolutionary history.     

Unrestrained poly-ADP-ribosylation provides insights into chromatin regulation and human disease

1. Download : Download high-res image (149KB)
2. Download : Download full-size image