Martin Lindahl
Programmerare
ATP-induced conformational dynamics in the AAA+ motor unit of magnesium chelatase.
Författare
Summary, in English
Mg-chelatase catalyzes the first committed step of the chlorophyll biosynthetic pathway, the ATP-dependent insertion of Mg(2+) into protoporphyrin IX (PPIX). Here we report the reconstruction using single-particle cryo-electron microscopy of the complex between subunits BchD and BchI of Rhodobacter capsulatus Mg-chelatase in the presence of ADP, the nonhydrolyzable ATP analog AMPPNP, and ATP at 7.5 A, 14 A, and 13 A resolution, respectively. We show that the two AAA+ modules of the subunits form a unique complex of 3 dimers related by a three-fold axis. The reconstructions demonstrate substantial differences between the conformations of the complex in the presence of ATP and ADP, and suggest that the C-terminal integrin-I domains of the BchD subunits play a central role in transmitting conformational changes of BchI to BchD. Based on these data a model for the function of magnesium chelatase is proposed.
Avdelning/ar
- Biokemi och Strukturbiologi
Publiceringsår
2010
Språk
Engelska
Sidor
354-365
Publikation/Tidskrift/Serie
Structure
Volym
18
Issue
3
Dokumenttyp
Artikel i tidskrift
Förlag
Cell Press
Ämne
- Biological Sciences
Status
Published
ISBN/ISSN/Övrigt
- ISSN: 0969-2126