Abstract The heat capacity plays a major role in the determination of energetics protein folding and molecular recognition. As such, better understanding this thermodynamic parameter its structural origin will provide new insights for development design strategies. In paper we have analyzed absolute proteins different conformations. results these studies indicate that three terms account protein: (1) one term depends only on primary or covalent structure contains contributions from...

The discovery that the protease from human immunodeficiency virus (HIV) belongs to aspartic family has generated renewed interest in this class of proteins. In paper, interactions endothiapepsin, an proteinase fungusEndothia parasitica,with inhibitor pepstatin A have been studied by high-sensitivity calorimetric techniques. These experiments permitted a complete characterization temperature and pH-dependence binding energetics. reaction is characterized negative intrinsic enthalpy heat...

The magnitude of the conformational entropy change experienced by peptide backbone upon protein folding was investigated experimentally and computational analysis. Experimentally, two different pairs mutants a 33 amino acid corresponding to leucine zipper region GCN4 were used for high-sensitivity microcalorimetric Each pair differed only having alanine or glycine at specific solvent-exposed position under conditions in which differences stability could be attributed unfolded state. studied...

Two effects are mainly responsible for the observed enthalpy change in protein unfolding: disruption of internal interactions within molecule (van der Waals, hydrogen bonds, etc.) and hydration groups that buried native state become exposed to solvent on unfolding. In traditional thermodynamic analysis, have usually been evaluated using data transfer small model compounds from gas phase water. The contribution interactions, other hand, estimated by subtracting experimental main drawback this...

INQUINOSA company dumped wastes from lindane production in Sabiñánigo (Huesca, Spain). In 2014, after discovering the underground migration of liquid HCH towards Gállego River, more than 400,000 tons contaminated materials were relocated old Bailín landfill to a new security cell. During transfer operations, small fraction ~ 100-200kg was dispersed area. We evaluated spatio-temporal dynamics HCH-isomers around landfill. Data five soil sampling campaigns have been used (2014-2022). Notably,...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTToward a solvent basicity scale: the calorimetry of pyrrole probeJavier Catalan, Javier Gomez, Angeles Couto, and Jose LaynezCite this: J. Am. Chem. Soc. 1990, 112, 5, 1678–1681Publication Date (Print):February 1, 1990Publication History Published online1 May 2002Published inissue 1 February 1990https://pubs.acs.org/doi/10.1021/ja00161a003https://doi.org/10.1021/ja00161a003research-articleACS PublicationsRequest reuse permissionsArticle...

The binding thermodynamics of the HIV-1 protease inhibitor acetyl pepstatin and substrate Val-Ser-Gln-Asn-Tyr-Pro-Ile-Val-Gln, corresponding to one cleavage sites in gag, gag-pol polyproteins, have been measured by direct microcalorimetric analysis. results indicate that peptide or is entropically driven; i.e., it characterized an unfavorable enthalpy a favorable entropy change, agreement with structure-based thermodynamic analysis based upon empirical parameterization energetics. Dissection...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAcidity and Basicity of Indazole its N-Methyl Derivatives in the Ground Excited StateJavier Catalan, Juan Carlos del Valle, Rosa M. Claramunt, Gerard Boyer, Jose Laynez, Javier Gomez, Pilar Jimenez, Francisco Tomas, ElgueroCite this: J. Phys. Chem. 1994, 98, 41, 10606–10612Publication Date (Print):October 1, 1994Publication History Published online1 May 2002Published inissue 1 October...

The Ring1B is a core subunit protein of the PRC1 (polycomb repressive complex 1), which plays key roles in regulation Homeobox gene expression, X-chromosome inactivation, stem cell self-renewal, and tumorigenesis. C-terminal region interacts with RYBP, transcriptional repressor transiently transfected cells, also M33, another involved mesoderm patterning. In this work, we show that domain Ring1B, C-Ring1B, dimer solution, dissociation constant 200 microM, as shown by NMR, ITC, analytical gel...

Tyrosine hydroxylase (TyrH) catalyzes the hydroxylation of tyrosine to form 3,4-dihydroxyphenylalanine, first step in synthesis catecholamine neurotransmitters. The protein contains a 159-residue regulatory domain (RD) at its N-terminus that forms dimers solution; N-terminal region RDTyrH (residues 1-71) is absent solution structure domain. We have characterized conformational stability two species (one containing and another lacking 64 residues) clarify how modulates RD. Under conditions...

Neuronal specification is regulated by the activity of transcription factors containing basic helix−loop−helix motif (bHLH); these regulating proteins include, among others, neurogenin (Ngn) family, related to atonal family genes. Neurogenin 1 (NGN1) a 237-residue protein that contains bHLH domain and involved in neuronal differentiation. In this work, we synthesized region NGN1 (bHLHN) comprising residues 90−150 full-length NGN1. The monomeric natively unfolded with pH-dependent premolten...

Complexes between chitosan and β-lactoglobulin (β-Lg) were investigated, their formation was found to depend on pH ionic strength. The electrostatic attraction the cationic polysaccharide negatively charged protein above its isoelectric point has been identified as main driving force in molecular recognition process. At low concentration, soluble complexes shown be formed, structural features characterized by circular dichroism (CD) steady-state fluorescence. Both overall secondary structure...

The type 1 HIV presents a conical capsid formed by approximately 1500 units of the protein, CA. Homodimerization CA via its C-terminal domain, CA-C, constitutes key step in virion assembly. CA-C dimerization is largely mediated reciprocal interactions between residues second alpha-helix. Here, we show that an N-terminal-acetylated and C-terminal-amidated peptide, CAC1, comprising sequence helix plus three flanking at each side, able to form complex with entire domain. Thermal denaturation...

Proteins entrapped in sol−gel matrices have been extensively studied during the last 15 years, showing that most of them can be encapsulated with retention their native structure and functionality enhanced stability. However, relatively little is known about structural dynamical details biomolecule−matrix interactions. To achieve this goal, model protein hen egg white lysozyme (HEWL) has prepared from tetraethyl orthosilicate through an alcohol-free route, photophysical properties its...

Virus capsid assembly constitutes an attractive target for the development of antiviral therapies; a few experimental inhibitors this process HIV-1 and other viruses have been identified by screening compounds or selection from chemical libraries. As different, novel approach we undertaken rational design peptides that could act as competitive mimicking structural elements involved in intersubunit interfaces. Several discrete interfaces formation mature through polymerization protein CA were...

This article reports on the interaction of conducting (K⁺) and blocking (Na⁺) monovalent metal ions with detergent-solubilized lipid-reconstituted forms K⁺ channel KcsA. Monitoring protein intrinsic fluorescence reveals that two bind competitively to KcsA distinct affinities (dissociation constants for KcsA·K⁺ KcsA·Na⁺ complexes ∼8 190 mm, respectively) induce different conformations ion-bound protein. The differences in binding affinity...

The prediction of binding affinities from structure is a necessary requirement in the development structure-based molecular design strategies. In this paper, structural parameterization energetics previously developed laboratory has been incorporated into algorithm aimed at identifying peptide conformations that minimize Gibbs energy. This approach employed mutants aspartic protease inhibitor pepstatin A. simplest strategy involves mutation and/or chain length modification wild-type...

Binding of K+ and Na+ to the potassium channel KcsA has been characterized from stabilization observed in heat-induced denaturation protein as ion concentration is increased. thermal known include (i) dissociation homotetrameric into its constituent subunits (ii) unfolding. The concentration-dependent changes stability protein, evaluated Tm value for thermal-induced may suggest existence both high- low-affinity binding sites KcsA, which lend support tenet that gating be governed by...

The sterile alpha motif (SAM) domain is a protein module of approximately 65 to 70 amino acids found in many diverse proteins whose functions range from signal transduction transcriptional repression. splice variant p73 (p73 α), homologue the tumor suppressor p53, has close its C-terminus SAM motif. Here, we report folding equilibrium properties α (SAMp73) by using different biophysical techniques (circular dichroism, fluorescence, and Fourier transform infrared spectroscopies, differential...