The experimental melting profile reported by Holtzer, M.E., Holtzer, A. and Skolnick, J. (Macromolecules 16 (1983) 173-180) for the rabbit alpha-tropomyosin dimer crosslinked at cysteine residue 190 has been analyzed using matrix methods. The configuration partition function employed includes a term arising from interactions at the crosslink site. This term, denoted by omega, is found to be smaller than 1, implying that events at the crosslink site resist helix formation by dimer. A theoretical analysis of the conformational restrictions imposed on the crosslink provides a satisfactory estimate of omega at high temperatures. Agreement deteriorates at lower temperatures, perhaps as a consequence of difficulty in establishing a reliable value for omega from analysis of the low-temperature circular dichroism data.
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http://dx.doi.org/10.1016/0167-4838(84)90119-5 | DOI Listing |
Mol Biol Cell
January 2025
MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK.
Nearly all mitochondrial proteins are imported into mitochondria from the cytosol. How nascent mitochondrial precursors acquire and sustain import-competence in the cytosol under normal and stress conditions is incompletely understood. Here, we show that under normal conditions, the Hsc70 and Hsp90 systems interact with and redundantly minimize precursor degradation.
View Article and Find Full Text PDFTrends Chem
November 2024
Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, NC 27402, United States.
BURP domain peptide cyclases, or BpCs (an abbreviation we recommend in this opinion), are an emerging class of copper enzymes which catalyze the oxidative macrocyclization of peptides in plants. A close examination of their novel protein fold, along with the unique dicopper active site that meticulously controls crosslinking within peptides, highlights how nature exploits intricate mechanistic strategies to achieve diverse functionalities. Here, we summarize recent discoveries regarding the sequence, structure, function, and proposed chemistry of BpCs.
View Article and Find Full Text PDFAnal Chem
January 2025
Center for Advanced Analytical Science, Guangzhou Key Laboratory of Sensing Materials and Devices, Guangdong Engineering Technology Research Center for Sensing Materials and Devices, School of Chemistry and Chemical Engineering, Guangzhou University, Guangzhou 510006, China.
Glycoproteins are of significant value to liquid biopsy of human diseases. Herein, we present a universal electrochemical platform for the amplified detection of glycoproteins, taking advantage of the glycan-matchmade multivalent decoration of enzyme labels for the enzymatic signal amplification. Briefly, the glycan-matchmade multivalent decoration involves two steps, i.
View Article and Find Full Text PDFPLoS One
January 2025
Manchester Cancer Research Centre, Division of Cancer Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom.
Non-covalent protein-protein interactions are one of the most fundamental building blocks in cellular signalling pathways. Despite this, they have been historically hard to identify using conventional methods due to their often weak and transient nature. Using genetic code expansion and incorporation of commercially available unnatural amino acids, we have developed a highly accessible method whereby interactions between biotinylated ubiquitin-like protein (UBL) probes and their binding partners can be stabilised using ultraviolet (UV) light-induced crosslinks.
View Article and Find Full Text PDFImmunohorizons
January 2025
Vatche and Tamar Manoukian Division of Digestive Diseases, Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA, United States.
Antibody (Ab) crosslinking of HLA class II (HLA II) molecules on the surface of endothelial cells (ECs) triggers proliferative and prosurvival intracellular signaling, which are implicated in promoting chronic Ab-mediated rejection (cAMR). Despite the importance of cAMR in transplant medicine, the mechanisms involved remain incompletely understood. Here, we examined the regulation of yes-associated protein (YAP) nuclear cytoplasmic localization and phosphorylation in human ECs challenged with Abs that bind HLA II, which are strongly associated with cAMR.
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