Visualizing the movement of the amphipathic helix in the respiratory complex I using a nitrile infrared probe and SEIRAS

FEBS Letters

article

Ana Filipa Santos Seica¹  Johannes Schimpf²  Thorsten Friedrich²  Petra Hellwig¹ 

[1] Laboratoire de Bioélectrochimie et Spectroscopie, Université de Strasbourg CNRS;Institut für Biochemie;University of Strasbourg Institute for Advanced Studies (USIAS)

关键词: infrared nitrile labels;    respiratory complex I;    SEIRAS;   

DOI  :  10.1002/1873-3468.13620

来源: John Wiley & Sons Ltd.

【 摘 要 】

Conformational movements play an important role in enzyme catalysis. Respiratory complex I, an L-shaped enzyme, connects electron transfer from NADH to ubiquinone in its peripheral arm with proton translocation through its membrane arm by a coupling mechanism still under debate. The amphipathic helix across the membrane arm represents a unique structural feature. Here, we demonstrate a new way to study conformational changes by introducing a small and highly flexible nitrile infrared (IR) label to this helix to visualize movement with surface-enhanced IR absorption spectroscopy. We find that labeled residues K551CL and Y590CL move to a more hydrophobic environment upon NADH reduction of the enzyme, likely as a response to the reorganization of the antiporter-like subunits in the membrane arm.

【 授权许可】

Unknown