A peptide mimetic of calcium.
Proteins of the troponin superfamily use homologous amino acid sequences as binding sites for Ca2+ and seem to have evolved from an ancestral Ca2+ binding site. We have utilized this ancestral sequence to construct a peptide (Ca(2+)-like peptide) with inverted hydropathy to the calcium-coordinating region of this protein. This synthetic peptide acted like Ca2+ in that (i) it increased the calmodulin-dependent hydrolysis of cAMP by phosphodiesterase, (ii) it interacted with EDTA, and (iii) it enhanced contraction of urinary bladder smooth muscle in vitro. Unlike Ca2+, the peptide's effects were destroyed by acid hydrolysis. These findings demonstrate the synthesis of a peptide that can substitute for Ca2+ and may have considerable utility for the study of Ca(2+)-regulated pathways and possible therapeutic value as a pharmacologic agent.
Dillon
J
J
Department of Physiology and Biophysics, University of Alabama, Birmingham 35294-0005.
Woods
W T
WT
Guarcello
V
V
LeBoeuf
R D
RD
Blalock
J E
JE
D000595:Amino Acid Sequence; D001665:Binding Sites; D002118:Calcium / Q000502:physiology*; D002147:Calmodulin / Q000378:metabolism*; D002942:Circular Dichroism; D000242:Cyclic AMP / Q000378:metabolism; D008969:Molecular Sequence Data; D009119:Muscle Contraction; D009130:Muscle, Smooth; D010455:Peptides / Q000737:chemistry* / Q000378:metabolism; D010727:Phosphoric Diester Hydrolases / Q000378:metabolism; D011485:Protein Binding; D011487:Protein Conformation; D013329:Structure-Activity Relationship
D002147:Calmodulin; D010455:Peptides; D000242:Cyclic AMP; D010727:Phosphoric Diester Hydrolases; D002118:Calcium