Purification and crystallization of the I subunit of magnesium chelatase

Abstract: The I subunit of magnesium chelatase is an AAA+ protein which binds and hydrolyzes ATP to drive the insertion of Mg2+ into protoporphyrin IX during bio-synthesis of bacteriochlorophyll and chlorophyll. The purification method and co-crystallization conditions of the Rhodobacter capsulatus BchI (bacteriochlorophyll Magnesium Chelatase I subunit) protein with either ADP or AMPPNP and crystallization conditions of Synechocystissp sp 6803 ChlI (chlorophyll Magnesium Chelatase I subunit) protein are described. This is the first report of a successful preparation of the crystals of BchI-ADP complex, the crystals of BchI-AMPPNP complex and crystals of ChlI protein. The crystals of both proteins will be used for further structure determination.