Protein transport via the cpTat pathway displays cooperativity and is stimulated by transport‐incompetent substrate

FEBS Letters

Theg, Steven M¹  Alder, Natahan N¹ 

[1] Division of Biological Sciences, Section of Plant Biology, University of California, One Shields Avenue, Davis, CA 95616, USA

关键词: cpTat pathway;    Thylakoid;    Kinetics;    Cooperativity;   

DOI  :  10.1016/S0014-5793(03)00231-X

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Kinetic analyses of cpTat-mediated protein transport across the thylakoid membrane were conducted, revealing three important characteristics of this translocation pathway. First, transport via the cpTAT system displays a non-Michaelis–Menten, sigmoidal rate–substrate relationship with an apparent Hill coefficient of 1.80, indicative of positive homotropic cooperativity. Second, the presence of transport-incompetent substrates was found not to competitively inhibit the translocation of transport-competent substrates. However, the presence of low concentrations of transport-incompetent protein enhances the transport of wild type substrate. Together, these findings suggest that interaction between Tat machinery components and both transport-competent and transport-incompetent protein may elicit a cooperative effect on the translocation rate.

【 授权许可】

Unknown