title: ATP-Binding site of annexin VI characterized by photochemical release of nucleotide and infrared difference spectroscopy.
abstract: Structural changes induced by nucleotide binding to porcine liver annexin VI (AnxVI) were probed by reaction-induced difference spectroscopy (RIDS). Photorelease of the nucleotide from ATP[Et(PhNO2)] produced RIDS of AnxVI characterized by reproducible changes in the amide I region. The magnitude of the infrared change was comparable to RIDS of other ATP-binding proteins, such as Ca(2+)-ATPase and creatine and arginine kinases. Analysis of RIDS revealed the existence of ATP-binding site(s) (K(d) < 1 microM) within the AnxVI molecule, comprising five to six amino acid residues located in the C-terminal portion of the protein molecule. The binding stoichiometry of ATP:AnxVI was determined as 1:1 (mol/mol). ATP, in the presence of Ca2+, induced changes in protein secondary structure reflected by a 5% decrease in alpha-helix content of the protein in favor of unordered structure. Such changes may influence the affinity of AnxVI for Ca2+ and modulate its interaction with membranes.
authors.affiliation: Department of Cellular Biochemistry, Department of Muscle Biochemistry, Nencki Institute of Experimental Biology, 3 Pasteur Street, Warsaw, 02-093, Poland. bandor@nencki.gov.pl
authors.forename: J
authors.initials: J
authors.lastname: Bandorowicz-Pikuła
authors.forename: A
authors.initials: A
authors.lastname: Wrzosek
authors.forename: M
authors.initials: M
authors.lastname: Danieluk
authors.forename: S
authors.initials: S
authors.lastname: Pikula
authors.forename: R
authors.initials: R
authors.lastname: Buchet
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism*; D017317:Annexin A6 / Q000737:chemistry* / Q000378:metabolism*; D001665:Binding Sites; D000252:Calcium-Transporting ATPases / Q000378:metabolism; D002942:Circular Dichroism; D006801:Humans; D007700:Kinetics; D016018:Least-Squares Analysis; D010446:Peptide Fragments / Q000737:chemistry; D010777:Photochemistry; D020033:Protein Isoforms / Q000737:chemistry / Q000378:metabolism; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods
chemical_list: D017317:Annexin A6; D010446:Peptide Fragments; D020033:Protein Isoforms; D000255:Adenosine Triphosphate; D000252:Calcium-Transporting ATPases