A photoaffinity ligand for the head-activator (HA) receptor from hydra was synthesized using solid-phase peptide synthesis and coupling of two HA peptides over their epsilon-amino groups of Lys7 with succinimidyl esters. The new ligand, Bpa-HA-HA bipeptide, contains one normal HA peptide and another where p-benzoylphenylalanine (Bpa) was added at the amino terminus to allow ultraviolet activation and Tyr11 instead of Phe11 for radioiodination. The 125I-Bpa-HA-HA bipeptide bound with nanomolar affinity to the HA receptor from the multiheaded mutant of Chlorohydra viridissima as measured in a filter assay. After photoaffinity labeling of the hydra membrane fraction, a 200-kDa band was detected using reducing or non-reducing SDS/PAGE and autoradiography. Unlabeled HA derivatives, but no other neuropeptides, inhibited the labeling. Competition experiments with HA-HA homobipeptide in the nanomolar range indicate that predominantly the low-affinity and not the high-affinity HA receptor was photolabeled. Further evidence that the labeled molecule is the HA receptor comes from specific photoaffinity labeling with a second ultraviolet-activatable ligand containing p-nitrophenylalanine. The HA receptor could be functionally solubilized with Triton X-100 or Chaps. In the solubilizate the 200-kDa HA receptor was photolabeled specifically by both ligands. Liquid-phase isoelectric focussing of the solubilizate indicated a pI of about 5.4 of the photolabeled molecule. After chemical deglycosylation with trifluoromethanesulfonic acid, the apparent molecular mass of the labeled molecule was decreased to 180 kDa, indicating that the receptor is glycosylated.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1111/j.1432-1033.1996.t01-1-00814.x | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Proteomic Profiling of Potential E6AP Substrates via Ubiquitin-based Photo-Crosslinking Assisted Affinity Enrichment.
Chembiochem
January 2025
University of Konstanz, Department of Chemistry, Universitaetsstrasse 10, 78457, Konstanz, GERMANY.
The ubiquitin (Ub) ligase E6AP, which is encoded by the UBE3A gene, has been associated with several human diseases including cervical cancer and Angelman syndrome, a neurodevelopmental disorder. Yet, our knowledge about disease-relevant substrates of E6AP is still limited. The formation of a thioester complex between Ub and the catalytic Cys residue of E6AP represents an essential intermediate step in E6AP-mediated ubiquitination.
View Article and Find Full Text PDFDevelopment of nucleus-targeted histone-tail-based photoaffinity probes to profile the epigenetic interactome in native cells.
Nat Commun
January 2025
School of Food and Biological Engineering, Engineering Research Center of Bio-process, Ministry of Education, Key Laboratory of Animal Source of Anhui Province, Hefei University of Technology, Hefei, 230009, China.
Dissection of the physiological interactomes of histone post-translational modifications (hPTMs) is crucial for understanding epigenetic regulatory pathways. Peptide- or protein-based histone photoaffinity tools expanded the ability to probe the epigenetic interactome, but in situ profiling in native cells remains challenging. Here, we develop a nucleus-targeting histone-tail-based photoaffinity probe capable of profiling the hPTM-mediated interactomes in native cells, by integrating cell-permeable and nuclear localization peptide modules into an hPTM peptide equipped with a photoreactive moiety.
View Article and Find Full Text PDFA propofol binding site in the voltage sensor domain mediates inhibition of HCN1 channel activity.
Sci Adv
January 2025
Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO 63110, USA.
Article Synopsis
- HCN ion channels play a key role in cellular activity and pain perception, with propofol acting as an analgesic by inhibiting their function.
- Researchers used a propofol analog to pinpoint binding sites on the human HCN1 isoform, revealing a specific pocket formed by certain residues in the channel.
- Mutations in this binding pocket affect propofol's ability to modulate HCN1 currents, highlighting its specific binding mechanism and offering insights for developing targeted HCN channel modulators.
CD63 as novel target for nanoemulsion-based F MRI imaging and drug delivery to activated cardiac fibroblasts.
Theranostics
January 2025
Department of Molecular Cardiology, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Düsseldorf, Germany.
Cardiac fibroblasts are activated following myocardial infarction (MI) and cardiac fibrosis is a major driver of the growing burden of heart failure. A non-invasive targeting method for activated cardiac fibroblasts would be advantageous because of their importance for imaging and therapy. Targeting was achieved by linking a 7-amino acid peptide (EP9) to a perfluorocarbon-containing nanoemulsion (PFC-NE) for visualization by F-combined with H-MRI.
View Article and Find Full Text PDFA subcellular selective APEX2-based proximity labeling used for identifying mitochondrial G-quadruplex DNA binding proteins.
Nucleic Acids Res
January 2025
Laboratory of Chemical Biology and State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 5625 Renmin Street, Changchun, Jilin 130022, P. R. China.
G-quadruplexes (G4s), as an important type of non-canonical nucleic acid structure, have received much attention because of their regulations of various biological processes in cells. Identifying G4s-protein interactions is essential for understanding G4s-related biology. However, current strategies for exploring G4 binding proteins (G4BPs) include pull-down assays in cell lysates or photoaffinity labeling, which are lack of sufficient spatial specificity at the subcellular level.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!