1o87
From Proteopedia
A NEW MGGDP COMPLEX OF THE FFH NG DOMAIN
Overview
Ffh is the signal sequence recognition and targeting subunit of the prokaryotic signal recognition particle (SRP). Previous structural studies of the NG GTPase domain of Ffh demonstrated magnesium-dependent and magnesium-independent binding conformations for GDP and GMPPNP that are believed to reflect novel mechanisms for exchange and activation in this member of the GTPase superfamily. The current study of the NG GTPase bound to Mg(2+)GDP reveals two new binding conformations-in the first the magnesium interactions are similar to those seen previously, however, the protein undergoes a conformational change that brings a conserved aspartate into its second coordination sphere. In the second, the protein conformation is similar to that seen previously, but the magnesium coordination sphere is disrupted so that only five oxygen ligands are present. The loss of the coordinating water molecule, at the position that would be occupied by the oxygen of the gamma-phosphate of GTP, is consistent with that position being privileged for exchange during phosphate release. The available structures of the GDP-bound protein provide a series of structural snapshots that illuminate steps along the pathway of GDP release following GTP hydrolysis.
About this Structure
1O87 is a Single protein structure of sequence from Thermus aquaticus. Full crystallographic information is available from OCA.
Reference
Novel protein and Mg2+ configurations in the Mg2+GDP complex of the SRP GTPase ffh., Focia PJ, Alam H, Lu T, Ramirez UD, Freymann DM, Proteins. 2004 Feb 1;54(2):222-30. PMID:14696184 Page seeded by OCA on Sat May 3 03:30:37 2008
