کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
2029951 | 1070994 | 2010 | 12 صفحه PDF | دانلود رایگان |

SummaryMg-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 Å, 14 Å, and 13 Å 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.
► The first quasi-atomic model of the Mg-chelatase AAA+ unit in the presence of ADP
► Cryo-EM three-dimensional reconstructions of the AAA+ complex in the presence of AMPPNP and ATP
► Conformational dynamics involving IntegrinI domains
Journal: - Volume 18, Issue 3, 10 March 2010, Pages 354–365