title: Studies of the calmodulin-binding site of twitchin with synthetic peptides using fluorescence and CD spectroscopy.
abstract: The calcium-dependent interaction of two synthetic peptides derived from the putative calmodulin-binding site in the protein kinase autoinhibitory region of twitchin was studied by fluorescence and CD spectroscopy. The peptides interacted with dansylcalmodulin in the presence of Ca2+ as shown by a change in the fluorescence emission spectra. Fluorescence titration of dansylcalmodulin with the peptides was used to quantify this interaction. The peptides appeared to assume a helical conformation in a non-polar environment as seen by CD spectroscopy. The ellipticity of Ca2+ calmodulin was enhanced in the presence of peptides compared with that of Ca2+ calmodulin and peptides alone, indicating that the peptides had formed a complex with calmodulin. These results support the assignment of the twitchin calmodulin-binding site.
authors.affiliation: Department of Physiology and Biophysics, Mount Sinai School of Medicine, New York, New York 10029, USA.
authors.forename: A
authors.initials: A
authors.lastname: Buku
authors.forename: W C
authors.initials: WC
authors.lastname: Probst
authors.forename: K R
authors.initials: KR
authors.lastname: Weiss
authors.forename: J
authors.initials: J
authors.lastname: Heierhorst
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001048:Aplysia; D029742:Caenorhabditis elegans Proteins; D002147:Calmodulin / Q000737:chemistry* / Q000378:metabolism; D002148:Calmodulin-Binding Proteins / Q000737:chemistry*; D002942:Circular Dichroism; D015801:Helminth Proteins / Q000737:chemistry* / Q000378:metabolism; D008969:Molecular Sequence Data; D009124:Muscle Proteins / Q000737:chemistry* / Q000378:metabolism; D010455:Peptides / Q000737:chemistry; D011485:Protein Binding; D013050:Spectrometry, Fluorescence; D014364:Tryptophan / Q000737:chemistry
chemical_list: D029742:Caenorhabditis elegans Proteins; D002147:Calmodulin; D002148:Calmodulin-Binding Proteins; D015801:Helminth Proteins; D009124:Muscle Proteins; D010455:Peptides; C489233:unc-22 protein, C elegans; D014364:Tryptophan