title: Validity of putative calcium binding loops of photoprotein aequorin.
abstract: Three peptides containing the putative Ca2+ binding loops, I, II and III, respectively, of a photoprotein, aequorin, from jellyfish Aequorea victoria were synthesized by a solid-phase procedure. The peptides bound Ca2+ with dissociation constants of 10(-3) to 10(-4) M, providing evidence for the assumption that Ca2+ binding loops are actually responsible for the binding of Ca2+. When the highly conserved 6th glycine residue in the 12-residue loops was replaced by arginine, no large effect was observed on Ca2+ binding. Exposure to a hydrophobic environment and the binding of Ca2+ brought about conformational changes to the peptides.
authors.affiliation: Department of Chemistry, Faculty of Science, Kyushu University, Fukuoka, Japan.
authors.forename: O
authors.initials: O
authors.lastname: Oishi
authors.forename: A
authors.initials: A
authors.lastname: Nagatomo
authors.forename: T
authors.initials: T
authors.lastname: Kohzuma
authors.forename: N
authors.initials: N
authors.lastname: Oda
authors.forename: T
authors.initials: T
authors.lastname: Miyazima
authors.forename: M
authors.initials: M
authors.lastname: Ohno
authors.forename: Y
authors.initials: Y
authors.lastname: Sakaki
mesh_terms: D000331:Aequorin / Q000737:chemistry / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D001059:Apoproteins / Q000737:chemistry; D002118:Calcium / Q000378:metabolism*; D002135:Calcium-Binding Proteins / Q000737:chemistry / Q000378:metabolism*; D002147:Calmodulin / Q000737:chemistry; D002413:Cations, Divalent; D002942:Circular Dichroism; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism; D011487:Protein Conformation; D011994:Recombinant Proteins; D037401:Scyphozoa
chemical_list: D001059:Apoproteins; D002135:Calcium-Binding Proteins; D002147:Calmodulin; D002413:Cations, Divalent; D010446:Peptide Fragments; D011994:Recombinant Proteins; C060014:apoaequorin; D000331:Aequorin; D002118:Calcium