Abstract
Natural-abundance 13C NMR spectra (at 15.04 MHz) of the polypeptide cardiac stimulant Anthopleurin-A are presented. The spectra contain many resolved one- and two-carbon resonances from carbonyl and aromatic carbons and a few resolved resonances from aliphatic carbons. Most of these have been assigned to individual carbons in the protein. The effect of pH on the 13C spectrum has been investigated. In conjunction with the resonance assignments, this yields estimates for the pK alpha values of the COOH-terminal and NH2-terminal residues, the side chain carboxylate of 1 of the 2 aspartic acid residues, and the imidazolium groups of the 2 histidine residues. The effects of the lanthanides La3+ and Gd3+ on the spectrum have also been studied. The results suggest that there are at least two binding sites, and further studies will be required to characterize these before they can be utilized as an aid in structural mapping. Finally, the results are discussed in relation to a postulated model for the mode of action of Anthopleurin-A.
Highlights
From the Roche Research Institute of Marine Pharmacology, Dee Why, N
The spectra contain many resolved oneand two-carbon resonances from carbonyl and aromatic carbons and a few resolved resonances from aliphatic carbons. Most of these have been assigned to individual carbons in the protein
Contains a number of resolved single-carbon resonances from carbonyl and aromatic carbons, and a few resolved resonances from aliphatic carbons
Summary
Study of (Received for publication, January 2, 1979, and in revised form, April 26, 1979). 13C NMR spectra (at 15.04 MHz) of the polypeptide cardiac stimulant Anthopleurin-A are presented. The spectra contain many resolved oneand two-carbon resonances from carbonyl and aromatic carbons and a few resolved resonances from aliphatic carbons Most of these have been assigned to individual carbons in the protein. Ods for the assignment of these resonances to specific amino acid residues in a protein have been presented [10]. Pharmacological studies [5, 6] indicate that AP-A’. We describe a study by natural-abundance carbon-13 NMR spectroscopy of the properties of AP-A in aqueous solution. NMR studies carried out at this field strength have shown that small native proteins yield many narrow single-carbon resonances from quaternary aromatic carbons [8,9,10].
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
