Abstract We describe the Chemical Probes Portal (https://www.chemicalprobes.org/), an expert review-based public resource to empower chemical probe assessment, selection and use. probes are high-quality small-molecule reagents, often inhibitors, that important for exploring protein function biological mechanisms, validating targets drug discovery. The publication, dissemination use of provide means accelerate functional annotation proteins, study proteins in cell biology, physiology, disease...

Abstract Herein, we used protein semisynthesis to investigate, for the first time, effect of lysine acetylation and phosphorylation, as well crosstalk between these modifications on structure aggregation mutant huntingtin exon1 (Httex1). Our results demonstrate that phosphorylation at T3 stabilizes α‐helical conformation N‐terminal 17 amino acids (Nt17) significantly inhibits Httex1. Acetylation single residues, K6, K9 or K15, had no Httex1 aggregation. Interestingly, but not reversed...

Chemical stimuli, generally constituted by small volatile organic molecules, are extremely important for the survival of different insect species. In course evolution, insects have developed very sophisticated biochemical systems binding and delivery specific semiochemicals to their cognate membrane-bound receptors. Chemosensory proteins (CSPs) a class soluble present at high concentration in chemosensory organs; they supposed be involved carrying chemical messages from environment this...

SummaryThe eukaryotic La protein recognizes the 3′ poly(U) sequences of nascent RNA polymerase III transcripts to assist folding and maturation. The ends such RNAs are bound by N-terminal domain (LaNTD). We have solved crystal structures four LaNTD:RNA complexes, each containing a different single-stranded oligomer, compared them structure previously published complex partially duplex RNA. presence purely in binding pocket at interface between motif RRM domains allows significantly closer...

canSAR (https://cansar.ai) is the largest public cancer drug discovery and translational research knowledgebase. Now hosted in its new home at MD Anderson Cancer Center, integrates billions of experimental measurements from across molecular profiling, pharmacology, chemistry, structural systems biology. Moreover, applies a unique suite machine learning algorithms designed to inform discovery. Here, we describe latest updates knowledgebase, including focus on significant novel data. These...

Macromolecular crowding ought to stabilize folded forms of proteins, through an excluded volume effect. This explanation has been questioned and observed effects attributed weak interactions with other cell components. Here we show conclusively that protein stability is affected by exclusion the effect more pronounced when crowder's size closer under study. Accurate evaluation made possible choice yeast frataxin, a undergoes cold denaturation above zero degrees, because unfolded form at low...

What is the mechanism that determines denaturation of proteins at low temperatures, which is, by now, recognized as a fundamental property all proteins? We present experimental evidence clarifies role specific interactions favor entrance water into hydrophobic core, originally proposed Privalov but never proved experimentally. By using combination molecular dynamics simulation, biology, and biophysics, we identified cluster negatively charged residues represents preferential gate for...

Crowding and confinement can affect protein stability, favouring the more compact species amongst folded unfolded conformations. An unbiased assessment of relative efficacy crowded confined environments has been hampered so far by paucity homogeneous comparisons on same protein. This paper reports spectroscopic studies yeast frataxin (Yfh1), a which provides an excellent model system for stability since it undergoes both cold heat denaturation at measurable temperatures. The Yfh1 was...

Three-dimensional domain swapping is a common phenomenon in pancreatic-like ribonucleases. In the aggregated state, these proteins acquire new biological functions, including selective cytotoxicity against tumour cells. RNase A able to dislocate both N- and C-termini, but usually this process requires denaturing conditions. contrast, bovine seminal ribonuclease (BS-RNase), which homo-dimeric protein sharing 80% of sequence identity with A, occurs natively as mixture swapped unswapped...

Eukaryotic initiation factor 5 (eIF5) plays multiple roles in translation initiation. Its N-terminal domain functions as a GTPase-activator protein (GAP) for GTP bound to eIF2, while its C-terminal region nucleates the interactions between factors, including eIF1, which acts inhibit hydrolysis or Pi release, and β subunit of eIF2. These proteins events they participate are critical accurate recognition correct start codon during Here, we report three-dimensional solution structure human...

Frataxins are a family of metal binding proteins associated with the human Friedreich's ataxia disease. Here, we have addressed effect non-specifically salts on stability yeast ortholog Yfh1. This protein is sensitive model since its strongly dependent environment, in particular ionic strength. Yfh1 also offers unique advantage that cold denaturation can be observed above freezing point water, thus allowing facile construction whole curve and hence measurement accurate thermodynamic...

We have exploited the capability of in-cell NMR to selectively observe flexible regions within folded proteins carry out a comparative study two members highly conserved frataxin family which are found both in prokaryotes and eukaryotes. They all contain globular domain shares more than 50% identity, eukaryotes is preceded by an N-terminal tail containing mitochondrial import signal. demonstrate that spectrum bacterial ortholog CyaY cannot be observed homologous E. coli system, although it...

The role of the denatured state in protein folding represents a key issue for proper evaluation kinetics and mechanisms. yeast ortholog human frataxin, mitochondrial essential iron homeostasis responsible Friedreich's ataxia, has been shown to undergo cold denaturation above 0 °C, absence chemical denaturants. This interesting property provides unique opportunity explore experimentally molecular mechanism both hot denaturation. In this work, we present characterization temperature urea...

As for a variety of other molecular recognition processes, conformational fluctuations play an important role in the cleavage polyubiquitin chains by Josephin domain ataxin-3. The interaction between and ubiquitin appears to be mediated motions α-helical hairpin that is unusual among deubiquitinating enzymes. Here, we characterized helical incorporating NMR measurements as replica-averaged restraints dynamics simulations, validating results small-angle x-ray scattering measurements. This...

An NMR study of the thermal stability titin I28 in temperature range from −16 to 65 °C showed that this protein can undergo cold denaturation at physiological conditions. This is second case a undergoing unbiased denaturation. Comparison curves buffer and crowded conditions shows it possible measure thermodynamics parameters for unfolding even when proteins aggregate high temperature. The use confinement polyacrylamide gels, with addition polyethylene glycol, allows easy access subzero...

Yfh1, the yeast ortholog of frataxin, is a protein limited thermodynamic stability which undergoes cold denaturation at temperatures above water freezing point. We have previously demonstrated that its strongly dependent on ionic strength and monovalent or divalent cations are able to considerably stabilize fold. Here, we present study folded state structural determinants lead strong salt dependence. demonstrate by nuclear magnetic resonance that, room temperature, Yfh1 exists as an...

Receptor tyrosine kinase FGFR3 is involved in many signaling networks and frequently mutated developmental disorders cancer. The Hsp90/Cdc37 chaperone system essential for function of normal neoplastic cells. Here we uncover the mechanistic inter-relationships between these proteins by combining approaches including NMR, HDX-MS, SAXS. We show that several disease-linked mutations convert to a stronger client, where determinant underpinning client strength involves an allosteric network...

Abstract The Chemical Probes Portal (www.chemicalprobes.org) is a free, public resource, based on expert-reviews, that supports the assessment, selection and use of small-molecule compounds qualify as chemical probes. These high-quality reagents are essential for exploring function individual proteins in complex biological systems, such cells organisms, validating potential therapeutic targets. reliable probes accelerates protein annotation basic studies informs drug discovery. However,...

In living systems, proteins are surrounded by many other macromolecules of different nature, at high total concentrations. the last few years, there has been an increasing effort to study biological directly in natural crowded environments, such as intact bacterial cells or mimicking crowding adding proteins, polysaccharides even synthetic polymers. We have recently proposed hen egg white (HEW) a suitable, medium conditions. Here, we show that HEW can increase dramatically aggregation...

The availability of solid state structures opioid receptors has prompted us to reconsider a crucial question concerning bioactive peptides: can their conformation be studied without any knowledge the structure receptors? possibility giving meaningful answer this query rests ultimately on ease dealing with flexibility peptides, and amongst them one most flexible enkephalin. All solution studies enkephalin hint at an inextricable mixture quasi isoenergetic conformers. In study we refer only...

(1)H, (15)N and (13)C chemical shift assignments are presented for the N-terminal region of human La protein, in apo 5'-UUUU RNA-bound state. Secondary structure analysis shows conformational changes interdomain linker upon complex formation.