Isolation and characterisation of a functional αβ heterodimer from the ATP synthase of Rhodospirillum rubrum

• Published in: FEBS letters Vol. 310; no. 2; pp. 187 - 192
• Main Authors: Andralojc, P.J., Harris, D.A.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 28.09.1992; Elsevier
• Subjects: Analytical, structural and metabolic biochemistry; ATP synthase; bacteriochlorophyll; BChl; Biological and medical sciences; carbonyl cyanide p-trifluoromethoxyphenyl hydrazone; catalytic portion of ATP synthase; CF1; dl-dithiothreitol; DTT; EF1; Enzyme reconstitution; Enzymes and enzyme inhibitors; F 1-ATPase; F1 from chloroplast thylakoids; F1 from Escherichia coli; F1 from Rhodospirillum rubrum; F1-ATPase; FCCP; Fundamental and applied biological sciences. Psychology; Heterodimer; high performance liquid chromatography; HPLC; Hydrolases; N-[2-hydroxy-1,1-bis(hydroxymethyl)ethyl]glycine; RF1; Rhodospirillum rubrum; SDS-PAGE; sodium dodecylsulphatepolyacrylamide gel electrophoresis; Subunit interactions; tricine; RF 1; DTT; Enzyme reconstitution; F 1-ATPase; FCCP; CF 1; Heterodimer; Subunit interactions; SDS-PAGE; ATP synthase; EF 1; Rhodospirillum rubrum; F 1; tricine; BChl; HPLC; F1-ATPase; Rhodospirillales; Enzymatic activity; Enzyme; Beta-Peptide chain; Molecular association; Bacteria; Alpha-Peptide chain; F0F1-ATPase; Rhodospirillaceae
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1016/0014-5793(92)81326-H

An αβ heterodimer of the F 1-ATPase of Rhodospirillum rubrum was isolated by extraction of chromatophores with LiCl. Each αβ heterodimer contains one tightly bound ADP, which is released upon removal of medium Mg 2+. The dimer can be reversibly dissociated by removal of Mg 2+-ions. The αβ heterodimer restores both ATP-synthetic and hydrolytic activities to LiCl-treated chromatophores, saturation being achieved at approximately 2 mmol αβ · mol BChl −1. The heterodimer itself hydrolyses Mg-ATP with an activity distinct from RF 1, being unaffected by azide or sulphite ions. The V max and K m (ATP) for this Mg 2+-dependent activity were 110 ± 10 nmol · min −1 mg protein −1 and 100 ± 30 μM, respectively. The K m did not differ significantly from that of RF 1.