The Stability and Formation of Native Proteins from Unfolded Monomers Is Increased through Interactions with Unrelated Proteins

The intracellular concentration of protein may be as high as 400 mg per ml; thus it seems inevitable that within the cell, numerous protein-protein contacts are constantly occurring. A basic biochemical principle states that the equilibrium of an association reaction can be shifted by ligand binding. This indicates that if within the cell many protein-protein interactions are indeed taking place, some fundamental characteristics of proteins would necessarily differ from those observed in traditional biochemical systems. Accordingly, we measured the effect of eight different proteins on the formation of homodimeric triosephosphate isomerase from Trypanosoma brucei (TbTIM) from guanidinium chloride unfolded monomers. The eight proteins at concentrations of micrograms per ml induced an important increase on active dimer formation. Studies on the mechanism of this phenomenon showed that the proteins stabilize the dimeric structure of TbTIM, and that this is the driving force that promotes the formation of active dimers. Similar data were obtained with TIM from three other species. The heat changes that occur when TbTIM is mixed with lysozyme were determined by isothermal titration calorimetry; the results provided direct evidence of the weak interaction between apparently unrelated proteins. The data, therefore, are strongly suggestive that the numerous protein-protein interactions that occur in the intracellular space are an additional control factor in the formation and stability of proteins

Microwave-assisted growth and characterization of water-dispersed CdTe/CdS core-shell nanocrystals with high photoluminescence

Journal of Physical Chemistry B1102713370-13374JPCB

The Coronavirus Anxiety Scale: Cross-national measurement invariance and convergent validity evidence.

Coronavirus Anxiety Scale (CAS) is a widely used measure that captures somatic symptoms of coronavirus-related anxiety. In a large-scale collaboration spanning 60 countries (Ntotal = 21,513), we examined the CAS’s measurement invariance and assessed the convergent validity of CAS scores in relation to the fear of COVID-19 (FCV-19S) and the satisfaction with life (SWLS-3) scales. We utilized both conventional exact invariance tests and alignment procedures, with results revealing that the single-factor model fit the data well in almost all countries. Partial scalar invariance was supported in a subset of 56 countries. To ensure the robustness of results, given the unbalanced samples, we employed resampling techniques both with and without replacement and found the results were more stable in larger samples. The alignment procedure demonstrated a high degree of measurement invariance with 9% of the parameters exhibiting noninvariance. We also conducted simulations of alignment using the parameters estimated in the current model. Findings demonstrated reliability of the means but indicated challenges in estimating the latent variances. Strong positive correlations between CAS and FCV-19S estimated with all three different approaches were found in most countries. Correlations of CAS and SWLS-3 were weak and negative, but significantly differed from zero in several countries. Overall, the study provided support for the measurement invariance of the CAS and offered evidence of its convergent validity while also highlighting issues with variance estimation.The work of Jorge Gaete was supported by Agencia Nacional de Investigacion y Desarrollo-Millennium Science Initiative Program, GrantNCS2021_081. The work of Adrian Stanciu was supported by GESIS-Leibniz Institute for the Social Sciences. The work of Shanu Shukla, Martina Klicperova-Baker, and Iva Polackova Solcova was supported by Narodni plan obnovy (NPO) "Systemic Risk Institute," Grant LX22NPO5101, funded by the European Union-Next Generation European Union (Ministry of Education, Youth, and Sports, NPO: EXCELES). The work of Hrant M. Avanesyan was supported by the financial support of the RA Science Committee, Project 21T-5A203. The work of Breeda McGrath was supported by American Psychological Association Division 48, Small Grants Program. The work of Judyta Borchet was supported by the Foundation for Polish Science, Scholarship START 006.2022. The work of Rubia Carla Formighieri Giordani was supported by the National Council for Scientific and Technological Development (Conselho Nacional de Desenvolvimento Cientifico e Tecnologico/CNPq), Project 401749/2022-3