TY - JOUR
T1 - ATP-Induced Conformational Dynamics in the AAA+ Motor Unit of Magnesium Chelatase
AU - Lundqvist, Joakim
AU - Elmlund, Hans
AU - Wulff, Ragna Peterson
AU - Berglund, Lisa
AU - Elmlund, Dominika
AU - Emanuelsson, Cecilia
AU - Hebert, Hans
AU - Willows, Robert D
AU - Hansson, Mats
AU - Lindahl, Martin
AU - Al-Karadaghi, Salam
PY - 2010/3/10
Y1 - 2010/3/10
N2 - 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 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.
AB - 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 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.
KW - CELLBIO
KW - PROTEINS
UR - http://www.scopus.com/inward/record.url?scp=77649111713&partnerID=8YFLogxK
U2 - 10.1016/j.str.2010.01.001
DO - 10.1016/j.str.2010.01.001
M3 - Article
C2 - 20223218
AN - SCOPUS:77649111713
SN - 0969-2126
VL - 18
SP - 354
EP - 365
JO - Structure
JF - Structure
IS - 3
ER -