Generation and Characterization of Site-Specifically Mono-Ubiquitylated p53.

The tumor suppressor p53 is regulated by various posttranslational modifications including different types of ubiquitylation, which exert distinct effects on p53. While modification by ubiquitin chains targets p53 for degradation, attachment of single ubiquitin moieties (mono-ubiquitylation) affects the intracellular location of p53 and/or its interaction with chromatin. However, how this is achieved at the molecular level remains largely unknown. Similarly, since p53 can be ubiquitylated at different lysine residues, it remains unclear if the eventual effect depends on the position of the lysine modified. Here, we combined genetic code expansion with oxime ligation to generate p53 site-specifically mono-ubiquitylated at position 120. We found that mono-ubiquitylation at this position neither interferes with p53 ubiquitylation by the E3 ligases HDM2 and E6AP in complex with the viral E6 oncoprotein nor affects p53 binding to a cognate DNA sequence. Thus, ubiquitylation per se does not affect physiologically relevant properties of p53.

Stigmatization of Chinese and Asian-looking people during the COVID-19 pandemic in Germany.

BACKGROUND: The outbreak and global spread of COVID-19 was accompanied by an increase in reports of stigmatization of Chinese and Asian-looking people. The behavioral immune system provides a framework for stigmatization in response to infectious disease threats. Specifically, stigmatization might increase with rising levels of infectious disease threat. The present study aimed to examine this hypothesis during the early phase of the COVID-19 pandemic. METHODS: As part of the "EUCLID" project ( https://euclid.dbvis.de ), a total of 5011 persons from Germany were surveyed via an online-questionnaire between February 2nd and April 3rd, 2020, covering the progression of the COVID-19 pandemic over three time periods which were defined by critical events. RESULTS: There was no evidence for an increase in the stigmatization of Chinese and Asian-looking people across three topics, that is personal proximity, air travel, and medical measures upon arrival from China. CONCLUSIONS: The present findings provide good news in that participants showed an adaptive response to the infectious disease threat rather than displaying increased stigmatization. Further research is necessary to specify the conditions that increase the risk of stigmatization in response to infectious disease threats.

Tuning ligand effects and probing the inner-workings of bond activation steps: generation of ruthenium complexes with tailor-made properties.

Activating chemical bonds through external triggers and understanding the underlying mechanism are at the heart of developing molecules with catalytic and switchable functions. Thermal, photochemical, and electrochemical bond activation pathways are useful for many chemical reactions. In this Article, a series of Ru(II) complexes containing a bidentate and a tripodal ligand were synthesized. Starting from all-pyridine complex 1(2+), the pyridines were stepwise substituted with "click" triazoles (2(2+)-7(2+)). Whereas the thermo- and photoreactivity of 1(2+) are due to steric repulsion within the equatorial plane of the complex, 3(2+)-6(2+) are reactive because of triazoles in axial positions, and 4(2+) shows unprecedented photoreactivity. Complexes that feature neither steric interactions nor axial triazoles (2(2+) and 7(2+)) do not show any reactivity. Furthermore, a redox-triggered conversion mechanism was discovered in 1(2+), 3(2+), and 4(2+). We show here ligand design principles required to convert a completely inert molecule to a reactive one and vice versa, and provide mechanistic insights into their functioning. The results presented here will likely have consequences for developing a future generation of catalysts, sensors, and molecular switches.

The Relation of Threat Level and Age With Protective Behavior Intentions During Covid-19 in Germany.

To contain the spread of Covid-19, engagement in protective behaviors across the population is of great importance. The present study investigated protective behavior intentions during the early phases of Covid-19 in Germany (February 2-April 3, 2020) as a function of threat level and age using data from 4,940 participants in the EUCLID project. Results indicated that the intention to engage in social distancing increased sharply with threat level. Intentions for personal hygiene also increased, although to a lesser extent. While age only had a small overall effect on behavioral intentions, differential patterns emerged. After the lockdown was introduced, the impact of age decreased for social distancing and hygiene behavior intentions but increased for seeing a doctor. Since containing the Covid-19 pandemic depends on high adoption rates of protective behaviors, future research should track sustained phases of the pandemic, including the easing of restrictions and possible new waves of infections.

ß- and γ-Amino Acids at α-Helical Interfaces: Toward the Formation of Highly Stable Foldameric Coiled Coils.

Since peptides are vital for cellular and pathogenic processes, much effort has been put into the design of unnatural oligomers that mimic natural peptide structures, also referred to as foldamers. However, to enable the specific application of foldamers, a thorough characterization of their interaction profiles in native protein environments is required. We report here the application of phage display for the identification of suitable helical environments for a sequence comprising an alternating set of ß- and γ-amino acids. In vitro selected sequences show that an increase in the hydrophobic surface area at the helical interface as well as the incorporation of a polar H-bond donor functionality can significantly improve interhelical interactions involving backbone-extended amino acids. Thus, our data provide insight into the principles of the rational design of foldameric inhibitors for protein-protein interactions.