Metal interactions with beef heart mitochondrial ATPase

• Published in: The Journal of biological chemistry Vol. 260; no. 10; pp. 6213 - 6218
• Main Authors: Daggett, S G, Gruys, K J, Schuster, S M
• Format: Journal Article
• Language: English
• Published: Bethesda, MD Elsevier Inc 25-05-1985; American Society for Biochemistry and Molecular Biology
• Subjects: Adenosine Triphosphate - metabolism; Analytical, structural and metabolic biochemistry; Animals; Binding Sites; Biological and medical sciences; Calcium - metabolism; Cattle; Electron Spin Resonance Spectroscopy; Enzymes and enzyme inhibitors; Fundamental and applied biological sciences. Psychology; Hydrolases; In Vitro Techniques; Magnesium - metabolism; Manganese - metabolism; Metals - metabolism; Mitochondria, Heart - metabolism; Proton-Translocating ATPases - metabolism; Heart; Absorption spectrometry; Mitochondria; Bovine; Hydrolase; Enzyme; ATPase; Animal; EPR spectrometry; Molecular interaction; Binding site; Metal
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1016/S0021-9258(18)88959-1

Atomic absorption and electron paramagnetic resonance spectroscopy were used to study the metal binding sites of beef heart mitochondrial ATPase (F1). Quantitative and qualitative properties of these sites are described. Two different separation techniques were able to distinguish two very tight sites from one tight (easily exchangeable) metal binding site on F1. Of these sites, two are specific for magnesium while one can be substituted with Mn2+, Co2+, or Zn2+. When MgAMP-PNP was incubated with F1, a fourth metal was bound to the enzyme. The carboxyl group modified by dicyclohexylcarbodiimide is shown not to be involved in binding of any of the tightly bound metals. Qualitative properties of the metal binding sites using the Mn2+-enzyme complex as a probe were ascertained using EPR at pH 6.8 and 8.0. CrATP and Mn2+ appear to bind to different metal sites on F1. The possible role of the metals in regulation of catalysis, and their relation to nucleotide binding is discussed.