Investigating the effects of different natural molecules on the structure and oligomerization propensity of hen egg-white lysozyme.

The formation of amyloid aggregates is the hallmark of systemic and neurodegenerative diseases, also known as amyloidosis. Many proteins have been found to aggregate into amyloid-like fibrils and thus process is recognized as general tendency of polypeptides. Inhibition of protein aggregation and fibril formation is thus one of the important strategies in the prevention and treatment of such disease.

Insights into Kinetics of Agitation-Induced Aggregation of Hen Lysozyme under Heat and Acidic Conditions from Various Spectroscopic Methods.

Protein misfolding and amyloid formation are an underlying pathological hallmark in a number of prevalent diseases of protein aggregation ranging from Alzheimer's and Parkinson's diseases to systemic lysozyme amyloidosis. In this context, we have used complementary spectroscopic methods to undertake a systematic study of the self-assembly of hen egg-white lysozyme under agitation during a prolonged heating in acidic pH. The kinetics of lysozyme aggregation, monitored by Thioflavin T fluorescence, dynamic light scattering and the quenching of tryptophan fluorescence by acrylamide, is described by a sigmoid curve typical of a nucleation-dependent polymerization process.

Clearance of genetic variants of amyloid β peptide by neuronal and non-neuronal cells.

The presence of senile plaques in the brain is one of the pathological hallmarks of Alzheimer's disease (AD). The biogenesis and clearance of the amyloid β peptide (A β ), the main component of the lesions, lie at the center of the pathogenesis of AD. In sporadic AD, the increase of A β levels seems to be indicative of failure of clearance mechanisms.

Acetonic extract of Buxus sempervirens induces cell cycle arrest, apoptosis and autophagy in breast cancer cells.

Plants are an invaluable source of potential new anti-cancer drugs. Here, we investigated the cytotoxic activity of the acetonic extract of Buxus sempervirens on five breast cancer cell lines, MCF7, MCF10CA1a and T47D, three aggressive triple positive breast cancer cell lines, and BT-20 and MDA-MB-435, which are triple negative breast cancer cell lines. As a control, MCF10A, a spontaneously immortalized but non-tumoral cell line has been used.

Processing of peptide and hormone precursors at the dibasic cleavage sites.

Many functionally important cellular peptides and proteins, including hormones, neuropeptides, and growth factors, are synthesized as inactive precursor polypeptides, which require post-translational proteolytic processing to become biologically active polypeptides. This is achieved by the action of a relatively small number of proteases that belong to a family of seven subtilisin-like proprotein convertases (PCs) including furin. In view of this, this review focuses on the importance of privileged secondary structures and of given amino acid residues around basic cleavage sites in substrate recognition by these endoproteases.

Clearance of amyloid-beta peptide by neuronal and non-neuronal cells: proteolytic degradation by secreted and membrane associated proteases.

Deposition of amyloid-beta peptide (Abeta) in the brain is an early and invariant feature of all forms of Alzheimer's disease (AD). As for all proteins or peptides, the steady-state level of Abeta peptide is determined not only by its production, but also by its degradation. So, overactive proteases involved in generating Abeta from amyloid precursor protein or underactive Abeta-degrading enzymes could lead to abnormal Abeta deposition in the brain.

Reactivity of basic amino acid pairs in prohormone processing: model of pro-ocytocin/neurophysin processing domain.

Statistical analysis of several potential dibasic cleavage sites reveals differences in the distribution of basic doublets when the in vivo cleaved sites were compared to those which are not cleaved. Analysis of the substrate specificity of protease Kex2 towards the pro-ocytocin/neurophysin processing domain (pro-OT/Np(7-15) with altered basic pairs shows a cleavage efficiency order in accord with the statistical data. Structural analysis of these substrates indicates that each basic pair is associated with a local and specific conformational change.