1ls1 | pdb_00001ls1
T. aquaticus Ffh NG Domain at 1.1A Resolution
Structural highlights
Function[SRP54_THEAQ] Involved in targeting and insertion of nascent membrane proteins into the cytoplasmic membrane. Binds to the hydrophobic signal sequence of the ribosome-nascent chain (RNC) as it emerges from the ribosomes. The SRP-RNC complex is then targeted to the cytoplasmic membrane where it interacts with the SRP receptor FtsY (By similarity).[HAMAP-Rule:MF_00306] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe NG domain of the prokaryotic signal recognition protein Ffh is a two-domain GTPase that comprises part of the prokaryotic signal recognition particle (SRP) that functions in co-translational targeting of proteins to the membrane. The interface between the N and G domains includes two highly conserved sequence motifs and is adjacent in sequence and structure to one of the conserved GTPase signature motifs. Previous structural studies have shown that the relative orientation of the two domains is dynamic. The N domain of Ffh has been proposed to function in regulating the nucleotide-binding interactions of the G domain. However, biochemical studies suggest a more complex role for the domain in integrating communication between signal sequence recognition and interaction with receptor. Here, we report the structure of the apo NG GTPase of Ffh from Thermus aquaticus refined at 1.10 A resolution. Although the G domain is very well ordered in this structure, the N domain is less well ordered, reflecting the dynamic relationship between the two domains previously inferred. We demonstrate that the anisotropic displacement parameters directly visualize the underlying mobility between the two domains, and present a detailed structural analysis of the packing of the residues, including the critical alpha4 helix, that comprise the interface. Our data allows us to propose a structural explanation for the functional significance of sequence elements conserved at the N/G interface. Structural basis for mobility in the 1.1 A crystal structure of the NG domain of Thermus aquaticus Ffh.,Ramirez UD, Minasov G, Focia PJ, Stroud RM, Walter P, Kuhn P, Freymann DM J Mol Biol. 2002 Jul 19;320(4):783-99. PMID:12095255[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences | ||||||||||||||||||||
