Novel protein and Mg2+ configurations in the Mg2+GDP complex of the SRP GTPase ffh.

ABSTRACT: 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

SUBMITTER: Focia PJ 

PROVIDER: S-EPMC3540803 | biostudies-literature | 2004 Feb

REPOSITORIES: biostudies-literature