Publications by authors named "Elliott J Stollar"

Article Synopsis
  • Charged residues on proteins are essential for stability and binding, but high net-charge regions can destabilize proteins while helping them interact with oppositely charged targets.
  • Researchers studied the folding of a specific yeast protein domain (SH3) and found that increased salt concentrations surprisingly stabilize its structure by mimicking interactions that occur during target binding.
  • The study revealed that while the protein experiences both hydrophobic collapse and electrostatic repulsion during folding, the formation of favorable interactions like salt-bridges and hydrogen bonds allows it to maintain a functional, folded state after overcoming initial challenges.
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Article Synopsis
  • Charged residues on proteins are crucial for stability and interactions, often creating regions that might destabilize proteins but are necessary for binding to oppositely charged targets.
  • The study found that increasing salt concentrations stabilizes the folding of the yeast SH3 domain by reducing electrostatic repulsion, thanks to effects like Debye-Huckel screening.
  • Experiments revealed that while the addition of urea or salt affects folding rates, the key folding events happen in the transition state, allowing the protein domain to efficiently fold and prepare for binding despite its high charge.
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Lecture capture (the real-time recording of live lectures) has become commonplace in higher education. It is popular with students who like the associated flexibility and believe that lecture recordings improve their grades. Here, we performed a survey (n = 694, 53% of the cohort) and set up focus groups (2 focus groups, 15 participants) to explore biological sciences students' perceptions of how lecture capture impacts their study behaviour when recordings are provided for every lecture and are made available to students without restriction.

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Almost all interactions and reactions that occur in living organisms involve proteins. The various biological roles of proteins include, but are not limited to, signal transduction, gene transcription, cell death, immune function, structural support, and catalysis of all the chemical reactions that enable organisms to survive. The varied roles of proteins have led to them being dubbed 'the workhorses of all living organisms'.

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Disordered proline-rich motifs are common across the proteomes of many species and are often involved in protein-protein interactions. Proline is a unique amino acid due to the covalent bond between the backbone nitrogen and the proline side chain. The resulting five-membered ring allows proline to sample the state about its peptide bond, which other residues cannot do as readily.

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Protein purification is imperative to the study of protein structure and function and is usually used in combination with biophysical techniques. It is also a key component in the development of new therapeutics. The evolving era of functional proteomics is fueling the demand for high-throughput protein purification and improved techniques to facilitate this.

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Structural biology is the study of the molecular arrangement and dynamics of biological macromolecules, particularly proteins. The resulting structures are then used to help explain how proteins function. This article gives the reader an insight into protein structure and the underlying chemistry and physics that is used to uncover protein structure.

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Protein-protein interactions are involved in a wide range of cellular processes. These interactions often involve intrinsically disordered proteins (IDPs) and protein binding domains. However, the details of IDP binding pathways are hard to characterize using experimental approaches, which can rarely capture intermediate states present at low populations.

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Article Synopsis
  • Protein purification is crucial for studying protein structure and developing new therapeutics, leading to a need for improved methods to purify multiple proteins simultaneously.* -
  • The researchers created a multi-column plate adapter (MCPA) to efficiently purify proteins using gravity or vacuum, allowing for the simultaneous purification of up to 96 samples with ease.* -
  • The MCPA system is adaptable for optimizing different purification parameters and produces enough protein for further analysis, making it a valuable tool in laboratory settings.*
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A need exists to develop bioinformatics for predicting differences in protein function, especially for members of a domain family who share a common fold, yet are found in a diverse array of proteins. Many domain families have been conserved over large evolutionary spans and representative genomic data during these periods are now available. This allows a simple method for grouping domain sequences to reveal common and unique/specific binding residues.

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The kinetics of folding and unfolding underlie protein stability and quantification of these rates provides important insights into the folding process. Here, we present a simple high throughput protein unfolding kinetic assay using a plate reader that is applicable to the studies of the majority of 2-state folding proteins. We validate the assay by measuring kinetic unfolding data for the SH3 (Src Homology 3) domain from Actin Binding Protein 1 (AbpSH3) and its stabilized mutants.

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There is increasing evidence for the functional importance of multiple dynamically populated states within single proteins. However, peptide binding by protein-protein interaction domains, such as the SH3 domain, has generally been considered to involve the full engagement of peptide to the binding surface with minimal dynamics and simple methods to determine dynamics at the binding surface for multiple related complexes have not been described. We have used NMR spectroscopy combined with isothermal titration calorimetry to comprehensively examine the extent of engagement to the yeast Abp1p SH3 domain for 24 different peptides.

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Saccharomyces cerevisiae Actin-Binding Protein 1 (Abp1p) is a member of the Abp1 family of proteins, which are in diverse organisms including fungi, nematodes, flies, and mammals. All proteins in this family possess an N-terminal Actin Depolymerizing Factor Homology (ADF-H) domain, a central Proline-Rich Region (PRR), and a C-terminal SH3 domain. In this study, we employed sequence analysis to identify additional conserved features of the family, including sequences rich in proline, glutamic acid, serine, and threonine amino acids (PEST), which are found in all family members examined, and two motifs, Conserved Fungal Motifs 1 and 2 (CFM1 and CFM2), that are conserved in fungi.

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Heterozygous mutations in MYH9, which encodes non-muscle myosin heavy chain IIA (MHC-IIA), result in autosomal dominant inherited MYH9-related disorders characterised by macro-thrombocytopenia, granulocyte inclusions, variable sensorineural deafness, cataracts and nephritis. MHC-IIA is assembled into a complex consisting of two pairs of light chains and two heavy chains, where the latter contain a neck region, SH3-like, motor and rod domains. We describe a patient with a Trp33Cys missense mutation in the SH3-like domain of MHC-IIA.

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SH3 domains, which are among the most frequently occurring protein interaction modules in nature, bind to peptide targets ranging in length from 7 to more than 25 residues. Although the bulk of studies on the peptide binding properties of SH3 domains have focused on interactions with relatively short peptides (less than 10 residues), a number of domains have been recently shown to require much longer sequences for optimal binding affinity. To gain greater insight into the binding mechanism and biological importance of interactions between an SH3 domain and extended peptide sequences, we have investigated interactions of the yeast Abp1p SH3 domain (AbpSH3) with several physiologically relevant 17-residue target peptide sequences.

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Many protein-protein interaction domains bind to multiple targets. However, little is known about how the interactions of a single domain with many proteins are controlled and modulated under varying cellular conditions. In this study, we investigated the in vivo effects of Abp1p SH3 domain mutants that incrementally reduce target-binding affinity in four different yeast mutant backgrounds in which Abp1p activity is essential for growth.

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Calcium-dependent protein kinases (CDPKs) are a class of calcium-binding sensory proteins that are found in plants and certain protozoa, including the causative agent of malaria, Plasmodium falciparum. CDPKs have diverse regulatory functions, including involvement in the triggering of the lytic cycle of malarial infection. CDPKs contain an autoinhibitory junction (J) region whose calcium-dependent interaction with the tethered regulatory calmodulin-like domain (CaM-LD) activates the catalytic kinase domain.

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We report an unusual interaction in which a water molecule approaches the heterocyclic nitrogen of tryptophan and histidine along an axis that is roughly perpendicular to the aromatic plane of the side chain. The interaction is distinct from the well-known conventional aromatic hydrogen-bond, and it occurs at roughly the same frequency in protein structures. Calculations indicate that the water-indole interaction is favorable energetically, and we find several cases in which such contacts are conserved among structural orthologs.

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We report the crystal structures and biophysical characterization of two stabilized mutants of the Drosophila Engrailed homeodomain that have been engineered to minimize electrostatic repulsion. Four independent copies of each mutant occupy the crystal lattice, and comparison of these structures illustrates variation that can be partly ascribed to networks of correlated conformational adjustments. Central to one network is leucine 26 (Leu26), which occupies alternatively two side chain rotameric conformations (-gauche and trans) and different positions within the hydrophobic core.

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