The plug domain of a neisserial TonB‐dependent transporter retains structural integrity in the absence of its transmembrane β‐barrel

FEBS Letters

Oke, M³  Sarra, R⁴  Gorringe, A.R¹  Buchanan, S.K³  Evans, R.W²  Farnaud, S²  Ghirlando, R³ 

[1] Research and Development, Health Protection Agency, Porton Down, Salisbury SP4 0JG, UK;Metalloprotein Research Group, Division of Biomolecular Sciences, The Randall Centre for Molecular Mechanisms of Cell Function, King's College London, 3.6A New Hunt's House, Guy's Campus, London SE1 1UL, UK;Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Department of Health and Human Services, Bethesda, MD 20892, USA;Department of Crystallography, Birkbeck College, Malet Street, London WC1E 7HX, UK

关键词: Transferrin binding protein A;    Iron transport;    Human transferrin;    TonB;    Neisseria meningitidis;    TbpA;    transferrin binding protein A;    TbpB;    transferrin binding protein B;    hTf;    human transferrin;    HRP;    horseradish peroxidase;    PBS;    phosphate-buffered saline;    CD;    circular dichroism;    NRMSD;    normalized root mean square deviation;   

DOI  :  10.1016/S0014-5793(04)00196-6

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Transferrin binding protein A (TbpA) is a TonB-dependent outer membrane protein expressed by pathogenic bacteria for iron acquisition from human transferrin. The N-terminal 160 residues (plug domain) of TbpA were overexpressed in both the periplasm and cytoplasm of Escherichia coli. We found this domain to be soluble and monodisperse in solution, exhibiting secondary structure elements found in plug domains of structurally characterized TonB-dependent transporters. Although the TbpA plug domain is apparently correctly folded, we were not able to observe an interaction with human transferrin by isothermal titration calorimetry or nitrocellulose binding assays. These experiments suggest that the plug domain may fold independently of the β-barrel, but extracellular loops of the β-barrel are required for ligand binding.

【 授权许可】

Unknown