EMD-1677
CryoEM 3D reconstruction of Rhodobacter capsulatus Mg-chelatase BchID complex in the presence of ATP
EMD-1677
Single-particle13.0 Å
Deposition: 08/01/2010Map released: 21/01/2010
Last modified: 13/03/2013
Sample Organism:
Rhodobacter capsulatus
Sample: Complex of Mg-chelatase subunits BchI and BchD in presence of ATP
Fitted models: 2x31 (Avg. Q-score: -0.001)
Deposition Authors: Lundqvist J, Elmlund H, Peterson-Wulff R, Elmlund D, Emanuelsson C, Hebert H, Willows R, Hansson M
,
Lindahl M,
Al-Karadaghi S
Sample: Complex of Mg-chelatase subunits BchI and BchD in presence of ATP
Fitted models: 2x31 (Avg. Q-score: -0.001)
Deposition Authors: Lundqvist J, Elmlund H, Peterson-Wulff R, Elmlund D, Emanuelsson C, Hebert H, Willows R, Hansson M
,
Lindahl M,
Al-Karadaghi S
ATP-induced conformational dynamics in the AAA+ motor unit of magnesium chelatase.
Lundqvist J,
Elmlund H,
Wulff RP,
Berglund L,
Elmlund D,
Emanuelsson C,
Hebert H,
Willows RD ,
Hansson M ,
Lindahl M,
Al-Karadaghi S
(2010) Structure , 18 , 354 - 365
,
Hansson M ,
Lindahl M,
Al-Karadaghi S
(2010) Structure , 18 , 354 - 365
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.
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.