A de novo lanthanide-binding coiled-coil polypeptide (MB1-2) was previously reported to self-assemble into a trimeric complex upon addition of Tb with a micromolar range dissociation constant. This study examines the effect of substitution of hydrophobic residues in heptad repeats of MB1-2 on the thermodynamic stability of the resulting Tb-peptide complex. Substitution of isoleucine to norleucine in each heptad repeat was assessed considering the greater accessible surface area of the latter and predicted increased hydrophobic interaction. Job's method of continuous variation using circular dichroism spectroscopy suggests a trimeric structure for the analog complex equivalent to that formed by MB1-2. The dissociation constant and CD spectra suggest that complex formation in the analog is more favorable as a result of ligand preorganization. In addition, thermal denaturation suggests greater stability of the Tb-MB1-2 Nle complex in comparison to the parent Tb-MB1-2. These results indicate improved stability of the complex class can be achieved through heptad repeat amino acid substitutions that increase peptide interchain interaction.
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http://dx.doi.org/10.1002/psc.3665 | DOI Listing |
J Am Chem Soc
December 2024
Laboratório Associado para a Química Verde (LAQV), Rede de Química e Tecnologia (REQUIMTE), Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal.
The photoswitching of supramolecular host-guest complexes is the basis of numerous molecularly controlled macroscopic functions, such as sol-gel transition, photopharmacology, the active transport of ions or molecules, light-powered molecular machines, and much more. The most commonly used systems employ photoactive azobenzene guests and synthetic host molecules, which bind as the stable isomers and dissociate as the forms after exposure to UV light. We present a new, extraordinarily efficient cucurbit[7]uril (CB7)/diazocine host/guest complex with inverted stability that self-assembles under UV irradiation and dissociates in the dark.
View Article and Find Full Text PDFAnal Biochem
December 2024
Advanced Medical & Dental Institute (AMDI), Universiti Sains Malaysia, Bertam, 13200 Kepala Batas, Penang, Malaysia. Electronic address:
Progesterone receptor is one of the markers used in antibody-based immunohistochemistry for the diagnostics of breast cancer. The shortcomings of antibodies raise the need to focus on alternative molecular recognition. Aptamers are chosen due to their many advantages as compared to antibodies.
View Article and Find Full Text PDFInt J Nanomedicine
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Division of Medical Physics and Biophysics, Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Medical University of Graz, Graz, 8010, Austria.
Background: Selenium (Se) is a vital micronutrient for maintaining homeostasis in the human body. Selenium nanoparticles (SeNPs) have demonstrated improved bioavailability compared to both inorganic and organic forms of Se. Therefore, supplementing with elemental Se in its nano-form is highly promising for biomedical applications related to Se deficiency.
View Article and Find Full Text PDFJ Am Soc Mass Spectrom
December 2024
School of Electronic and Information Engineering, Soochow University, Suzhou 215006, China.
Tandem mass spectrometry (MS) is one of the most effective methods to obtain the structures of organic molecules, enabling the observation of multigenerational ion fragments. Collision-induced dissociation (CID) is currently the most mature technique for mass spectrometry analysis. Ion trap mass spectrometry (ITMS) is favored for on-site detection field, due to its ability of MS analysis with a single trap and its small size.
View Article and Find Full Text PDFSmall
December 2024
State Key Laboratory of Bio-fibers and Eco-textiles, Collaborative Innovation Center of Shandong Marine Biobased Fibers and Ecological Textiles, Institute of Marine Biobased Materials, College of Materials Science and Engineering, Qingdao University, Qingdao, 266071, P. R. China.
Organic small molecules (OSMs) with well-defined structures are crucial integral components of cathode catalysts for fuel cells. Despite the acknowledged potential of heteroatom doping to enhance the catalytic performance of metal-free carbon-based catalysts, there exists a notable gap in conducting molecular structure and catalytic activity, particularly under the premise of maintaining a constant molecular skeleton and with a clear molecular structure. Herein, the charge distribution is modulated by introducing different chalcogens into the same molecular skeleton through main-group engineering.
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