Recombinant production, characterization and industrial application testing of a novel acidic exo/endo-chitinase from Rasamsonia emersonii.

An acid-active exo/endo-chitinase; comprising a GH18 catalytic domain and substrate insertion domain; originating from the thermophilic filamentous fungus Rasamsonia emersonii, was expressed in Pichia pastoris. In silico analysis including phylogenetic analysis, and recombinant production, purification, biochemical characterisation, and industrial application testing, was carried out. The expressed protein was identified by SDS-PAGE as a smear from 56.

Cellular toxicity of yeast prion protein Rnq1 can be modulated by N-terminal wild type huntingtin.

Aggregation of the N-terminal human mutant huntingtin and the consequent toxicity in the yeast model of Huntington's disease (HD) requires the presence of Rnq1 protein (Rnq1p) in its prion conformation [RNQ1(+)]. The understanding of interaction of wild-type huntingtin (wt-Htt) with the amyloidogenic prion has some gaps. In this work, we show that N-terminal fragment of wt-Htt (N-wt-Htt) ameliorated the toxic effect of [RNQ1(+)] depending on expression levels of both proteins.

Activation of salt shock response leads to solubilisation of mutant huntingtin in Saccharomyces cerevisiae.

Formation of cytoplasmic and nuclear aggregates is a hallmark of Huntington's disease (HD). Inhibition of aggregation of mutant huntingtin has been suggested to be a feasible approach to slow down the progress of this neurodegenerative disorder. Exposure to environmental stimuli leads to the activation of the stress response machinery of the cell.

Roles of Hsp104 and trehalose in solubilisation of mutant huntingtin in heat shocked Saccharomyces cerevisiae cells.

Inhibition of huntingtin aggregation, either in the nucleus and/or in the cytosol, has been identified as a major strategy to ameliorate the symptoms of Huntington's disease. Chaperones and other protein stabilisers would thus be key players in ensuring the correct folding of the amyloidogenic protein and its expression in the soluble form. By transient activation of the global heat stress response in Saccharomyces cerevisiaeBY4742, we show that heterologous expression of mutant huntingtin (103Q-htt) could be modulated so that the protein was partitioned off in the soluble fraction of the cytosol.

Cytotoxicity of mutant huntingtin fragment in yeast can be modulated by the expression level of wild type huntingtin fragment.

Conflicting reports exist in the literature regarding the role of wild-type huntingtin in determining the toxicity of the aggregated, mutant huntingtin in Huntington's disease (HD). Some studies report the amelioration of toxicity of the mutant protein in the presence of the wild-type protein, while others indicate sequestration of the wild-type protein by mutant huntingtin. Over the years, yeast has been established as a valid model organism to study molecular changes associated with HD, especially at the protein level.

Hsp104 as a key modulator of prion-mediated oxidative stress in Saccharomyces cerevisiae.

Maintenance of cellular redox homoeostasis forms an important part of the cellular defence mechanism and continued cell viability. Despite extensive studies, the role of the chaperone Hsp104 (heat-shock protein of 102 kDa) in propagation of misfolded protein aggregates in the cell and generation of oxidative stress remains poorly understood. Expression of RNQ1-RFP in Saccharomyces cerevisiae cells led to the generation of the prion form of the protein and increased oxidative stress.