Nuclear magnetic resonance (NMR) spectroscopy was used to study a cyclic peptide derived from the amino-terminal copper-and-nickel-binding (ATCUN) motif. The three-dimensional structure of the unliganded peptide in aqueous solution was solved by simulated annealing using distance constraints derived from Nuclear Overhauser Effects. A structural model for the Ni(II)-bound complex was also produced based on NMR evidence and prior spectroscopic data, which are consistent with crystal structures of linear ATCUN complexes. Structural interpolation, or "morphing," was used to understand the transition of this highly structured cyclic peptide from its unliganded structure to its metal-ion-bound structure.
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http://dx.doi.org/10.1016/j.tet.2014.07.083 | DOI Listing |
BMJ Case Rep
January 2025
Diabetes, Greenlane Hospital, Auckland, Auckland, New Zealand.
A woman in her 40s presented with severe post-bariatric hypoglycaemia that persisted despite nutritional therapy and pharmacological therapy with acarbose and subcutaneous octreotide with meals. The nutritional limitations were difficult to sustain, and she developed adverse effects to the pharmacological therapy, and hence, doses could not be increased. She was subsequently treated with subcutaneous octreotide via an insulin pump, with a continuous basal rate and additional bolus doses with meals.
View Article and Find Full Text PDFChem Sci
January 2025
Department of Chemistry, Imperial College London Molecular Sciences Research Hub, 82 Wood Lane, White City Campus London W12 0BZ UK
The blood-brain-barrier prevents many imaging agents and therapeutics from being delivered to the brain that could fight central nervous system diseases such as Alzheimer's disease and strokes. However, techniques such as the use of stapled peptides or peptide shuttles may allow payloads through, with bioconjugation achieved bio-orthogonal tetrazine/norbornene click chemistry. A series of lanthanide-tetrazine probes have been synthesised herein which could be utilised in bio-orthogonal click chemistry with peptide-based delivery systems to deliver MRI agents through the blood-brain-barrier.
View Article and Find Full Text PDFACS Cent Sci
January 2025
Centre for Inflammation Research, The University of Edinburgh, EH16 4UU Edinburgh, U.K.
The cellular uptake routes of peptides and proteins are complex and diverse, often handicapping therapeutic success. Understanding their mechanisms of internalization requires chemical derivatization with approaches that are compatible with wash-free and real-time imaging. In this work, we developed a new late-stage labeling strategy for unprotected peptides and proteins, which retains their biological activity while enabling live-cell imaging of uptake and intracellular trafficking.
View Article and Find Full Text PDFAnal Chem
January 2025
Department of Laboratory Medicine, Clinical Laboratory Medicine Research Center of West China Hospital, Med+X Center for Manufacturing, Department of Rheumatology & Immunology, National Clinical Research Center for Geriatrics, Department of Gynecology of West China Tianfu Hospital, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China.
Homogeneous analysis techniques offer several advantages as alternatives to heterogeneous immunoassays, such as simplicity and rapidity. In this study, a visual homogeneous immunoassay without a labeling process was developed based on target-induced steric hindrance to regulate competitive recognition mechanism. Specifically, as the analyte concentration varies, the change of microenvironment based on steric hindrance could affect the recognition of Cu by signal probes.
View Article and Find Full Text PDFProtein Sci
February 2025
Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, Alberta, Canada.
Polymyxins are last-resort antimicrobial peptides administered clinically against multi-drug resistant bacteria, specifically in the case of Gram-negative species. However, an increasing number of these pathogens employ a defense strategy that involves a relay of enzymes encoded by the pmrE (ugd) loci and the arnBCDTEF operon. The pathway modifies the lipid-A component of the outer membrane (OM) lipopolysaccharide (LPS) by adding a 4-amino-4-deoxy-l-arabinose (L-Ara4N) headgroup, which renders polymyxins ineffective.
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