Detergent‐solubilized Escherichia coli cytochrome bo 3 ubiquinol oxidase: a monomeric, not a dimeric complex

FEBS Letters

Robinson, Neal C²  Musatov, Andrej²  Gennis, Robert B¹  Demeler, Borries²  Ortega-Lopez, Jaime³  Osborne, Jeffrey P¹ 

[1] Department of Biochemistry and Chemistry, University of Illinois, Urbana, IL 61801, USA;Department of Biochemistry, The University of Texas Health Science Center, 7703 Floyd Curl Dr., San Antonio, TX 78284-7760, USA;Departamento de Biotecnologia y Bioingenirı́a, CINVESTAV-IPN, Mexico City, Mexico

关键词: Cytochrome bo ubiquinol oxidase;    Sedimentation velocity;    Sedimentation equilibrium;    Computer analysis;    Escherichia coli;   

DOI  :  10.1016/S0014-5793(99)01020-0

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The protein molecular weight, M _r, and hydrodynamic radius, R _s, of Triton X-100-solubilized Escherichia coli cytochrome bo ₃ were evaluated by computer fitting of sedimentation velocity data with finite element solutions to the Lamm equation. Detergent-solubilized cytochrome bo ₃ sediments as a homogeneous species with an s _20,w of 6.75 s and a D _20,w of 3.71×10⁻⁷ cm²/s, corresponding to a R _s of 5.8 nm and a M _r of 144 000±3500. The protein molecular weight agrees very well with the value of 143 929 calculated from the four known subunit sequences and the value of 143 025 measured by MALDI mass spectrometry for the histidine-tagged enzyme. We conclude that detergent-solubilized E. coli ubiquinol oxidase is a monomeric complex of the four known subunits.

【 授权许可】

Unknown