Structure-function relationships in the polypeptide cardiac stimulant, anthopleurin-A. Effects of limited proteolysis by trypsin.
Selective proteolysis of the polypeptide cardiostimulant anthopleurin-A by trypsin introduces a single break in the polypeptide backbone on the C-terminal side of Arg14. The resulting derivative is devoid of any cardiostimulant activity. The structural changes which accompany this loss of activity have been examined by one- and two-dimensional 1H-NMR spectroscopy. It is shown that the overall backbone folding of anthopleurin-A is conserved on digestion, with some structural changes occurring for residues which are adjacent to the site of cleavage by trypsin. Thus, although previous NMR studies on anthopleurin-A indicate that the region surrounding Arg14 is devoid of any ordered structure, it appears that some degree of structural integrity is required to allow the essential side chains to adopt the conformation necessary to produce a cardiostimulant effect.
Gould
A R
AR
School of Biochemistry, University of New South Wales, Kensington, Australia.
Mabbutt
B C
BC
Norton
R S
RS
D000595:Amino Acid Sequence; D000818:Animals; D002316:Cardiotonic Agents / Q000494:pharmacology*; D002851:Chromatography, High Pressure Liquid; D006168:Guinea Pigs; D006321:Heart / Q000187:drug effects*; D006325:Heart Atria / Q000187:drug effects; D066298:In Vitro Techniques; D036341:Intercellular Signaling Peptides and Proteins; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000302:isolation & purification / Q000494:pharmacology*; D010455:Peptides / Q000235:genetics / Q000302:isolation & purification / Q000494:pharmacology*; D011487:Protein Conformation; D012615:Sea Anemones; D012689:Sequence Homology, Nucleic Acid; D014357:Trypsin
D002316:Cardiotonic Agents; D036341:Intercellular Signaling Peptides and Proteins; D010446:Peptide Fragments; D010455:Peptides; C012746:anthopleurin-A; D014357:Trypsin