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ATP-induced conformational dynamics in the AAA+ motor unit of magnesium chelatase.
- Source :
-
Structure (London, England : 1993) [Structure] 2010 Mar 10; Vol. 18 (3), pp. 354-65. - Publication Year :
- 2010
-
Abstract
- 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.
- Subjects :
- Adenosine Triphosphate metabolism
Amino Acid Sequence
Bacterial Proteins metabolism
Cryoelectron Microscopy
Genes, Bacterial
Lyases metabolism
Models, Molecular
Molecular Sequence Data
Protein Conformation
Rhodobacter capsulatus metabolism
Adenosine Triphosphate chemistry
Bacterial Proteins chemistry
Lyases chemistry
Subjects
Details
- Language :
- English
- ISSN :
- 1878-4186
- Volume :
- 18
- Issue :
- 3
- Database :
- MEDLINE
- Journal :
- Structure (London, England : 1993)
- Publication Type :
- Academic Journal
- Accession number :
- 20223218
- Full Text :
- https://doi.org/10.1016/j.str.2010.01.001