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

FEBS Letters

Harris, D.A.¹  Andralojc, P.J.¹ 

[1] Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK

关键词: Rhodospirillum rubrum;    Enzyme reconstitution;    ATP synthase;    F1-ATPase;    Subunit interactions;    Heterodimer;    F1;    catalytic portion of ATP synthase;    RF1;    F1 from Rhodospirillum rubrum;    EF1;    F1 from Escherichia coli;    CF1;    F1 from chloroplast thylakoids;    HPLC;    high performance liquid chromatography;    DTT;    dl-dithiothreitol;    SDS-PAGE;    sodium dodecylsulphatepolyacrylamide gel electrophoresis;    tricine;    N-[2-hydroxy-1;    1-bis(hydroxymethyl)ethyl]glycine;    BChl;    bacteriochlorophyll;    FCCP;    carbonyl cyanide p-trifluoromethoxyphenyl hydrazone;   

DOI  :  10.1016/0014-5793(92)81326-H

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

An αβ heterodimer of the F₁-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 Mg²⁺. The dimer can be reversibly dissociated by removal of Mg²⁺-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 RF₁, being unaffected by azide or sulphite ions. The V _max and K _m (ATP) for this Mg²⁺-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 RF₁.

【 授权许可】

Unknown