Brown human hair was bleached three times (45 min × 3) and four times (45 min × 3 + 15 min) with commercial formulations containing persulfate salts and hydrogen peroxide. The hair samples were characterized by Raman and IR spectroscopy in the Attenuated Total Reflectance (ATR) mode to gain more insights into the possible secondary structure and C-C-S-S-C-C conformational changes induced by bleaching. The latter were evaluated through band-fitting procedures; the relative content of the disulfide bridges and oxidized sulfur species (cysteic acid, Bunte salt, cystine oxides) was assessed. The observed conformational changes could be significant in developing restoring agents to be used after hair decoloration. The use of two different spectroscopic techniques allowed to discriminate the information coming from the cortical region of hair (Raman) and the cuticle (ATR/IR). This article refers to "Structural investigation on damaged hair keratin treated with α,β-unsaturated Michael acceptors used as repairing agents" (Di Foggia et al., Int. J. Biol. Macromol. 167 (2021) 620-632 https://doi.org/10.1016/j.ijbiomac.2020.11.194).
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http://dx.doi.org/10.1016/j.dib.2021.107439 | DOI Listing |
PLoS Comput Biol
January 2025
Department of Physics, University of Toronto, Toronto, Ontario, Canada.
Efflux pumps that transport antibacterial drugs out of bacterial cells have broad specificity, commonly leading to broad spectrum resistance and limiting treatment strategies for infections. It remains unclear how efflux pumps can maintain this broad spectrum specificity to diverse drug molecules while limiting the efflux of other cytoplasmic content. We have investigated the origins of this broad specificity using theoretical models informed by the experimentally determined structural and kinetic properties of efflux pumps.
View Article and Find Full Text PDFChem Biodivers
January 2025
SRM Institute of Science and Technology - NCR Campus, chemistry, Department of Chemistry, SRM Institute of Science and Technology, Delhi NCR Camp, India, 241405, Modinagar, INDIA.
This review paper provides an inclusive overview of the intricate interactions amid ionic liquids (ILs) and essential biomacromolecules, mainly Hemoglobin (Hb), Bovine Serum Albumin (BSA), Human Serum Albumin (HSA), and Calf Thymus-DNA (CT-DNA). ILs have recently become a topic of great attention because of their inimitable physicochemical properties and potential uses in different fields. The review systematically explores the binding mechanisms, thermodynamics, and structural changes induced by ILs on Hb, BSA, HSA, and CT-DNA using spectroscopic, thermodynamic, and computational techniques.
View Article and Find Full Text PDFSoft Matter
January 2025
College of Chemistry, Sichuan University, Chengdu 610064, China.
Biomolecules usually adopt ubiquitous circular structures which are important for their functionality. Based on three-dimensional Langevin dynamics simulations, we investigate the conformational change of a polymer confined in a spherical cavity. Both passive and active polymers with either homogeneous or heterogeneous stiffness are analyzed in a comparative manner.
View Article and Find Full Text PDFAngiotensin-I converting enzyme (ACE) regulates the levels of disparate bioactive peptides, notably converting angiotensin-I to angiotensin-II and degrading amyloid beta. ACE is a heavily glycosylated dimer, containing 4 analogous catalytic sites, and exists in membrane bound and soluble (sACE) forms. ACE inhibition is a frontline, FDA-approved, therapy for cardiovascular diseases yet is associated with significant side effects, including higher rates of lung cancer.
View Article and Find Full Text PDFWe introduce Hydrogen-Exchange Experimental Structure Prediction (HX-ESP), a method that integrates hydrogen exchange (HX) data with molecular dynamics (MD) simulations to accurately predict ligand binding modes, even for targets requiring significant conformational changes. Benchmarking HX-ESP by fitting two ligands to PAK1 and four ligands to MAP4K1 (HPK1), and comparing the results to X-ray crystallography structures, demonstrated that HX-ESP successfully identified binding modes across a range of affinities significantly outperforming flexible docking for ligands necessitating large conformational adjustments. By objectively guiding simulations with experimental HX data, HX-ESP overcomes the long timescales required for binding predictions using traditional MD.
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