2X31

Modelling of the complex between subunits BchI and BchD of magnesium chelatase based on single-particle cryo-EM reconstruction at 7.5 ang

Summary for 2X31

• Entry DOI: 10.2210/pdb2x31/pdb
• Related: 1G8P
• EMDB information: 1676 1677 1678
• Descriptor: MAGNESIUM-CHELATASE 60 KDA SUBUNIT, MAGNESIUM-CHELATASE 38 KDA SUBUNIT (2 entities in total)
• Functional Keywords: ligase, bacteriochlorophyll biosynthesis, photosynthesis
• Biological source: RHODOBACTER CAPSULATUS; More
• Total number of polymer chains: 12
• Total formula weight: 345678.59

Authors

Lunqvist, J.,Elmlund, H.,Peterson Wulff, R.,Berglund, L.,Elmlund, D.,Emanuelsson, C.,Hebert, H.,Willows, R.D.,Hansson, M.,Lindahl, M.,Al-Karadaghi, S. (deposition date: 2010-01-19, release date: 2010-11-10, Last modification date: 2024-05-08)

Primary citation

Lundqvist, J.,Elmlund, H.,Wulff, R.P.,Berglund, L.,Elmlund, D.,Emanuelsson, C.,Hebert, H.,Willows, R.D.,Hansson, M.,Lindahl, M.,Al-Karadaghi, S.
ATP-Induced Conformational Dynamics in the Aaa+ Motor Unit of Magnesium Chelatase.
Structure, 18:354-, 2010

PubMed 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.

PubMed: 20223218
DOI: 10.1016/J.STR.2010.01.001

Experimental method

ELECTRON MICROSCOPY (7.5 Å)