ATP-Induced Conformational Dynamics in the AAA plus Motor Unit of Magnesium Chelatase
2010 (English)In: Structure, ISSN 0969-2126, E-ISSN 1878-4186, Vol. 18, no 3, 354-365 p.Article in journal (Refereed) Published
Mg-chelatase catalyzes the first committed step of the chlorophyll biosynthetic pathway, the ATP-dependent insertion of Mg2+ 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 angstrom, 14 angstrom, and 13 angstrom 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 ATIP 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.
Place, publisher, year, edition, pages
2010. Vol. 18, no 3, 354-365 p.
protoporphyrin ix chelatase, rhodobacter-sphaeroides, chlorophyll, biosynthesis, synechocystis pcc6803, electron-microscopy, barley, mutants, mg-chelatase, swiss-model, subunit-d, protein
Biochemistry and Molecular Biology
IdentifiersURN: urn:nbn:se:kth:diva-19306DOI: 10.1016/j.str.2010.01.001ISI: 000275492000012OAI: oai:DiVA.org:kth-19306DiVA: diva2:337353
QC 201101142010-08-052010-08-052012-03-21Bibliographically approved