1yr9
From Proteopedia
PAB0955 crystal structure : a GTPase in GDP and PO4 bound form from Pyrococcus abyssi
Structural highlights
FunctionGPN_PYRAB Small GTPase that may be involved in genome maintenance. Has weak intrinsic GTPase activity but displays no ATPase activity.[1] 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 human XAB1/MBDin GTPase and its close homologues form one of the ten phylogenetically distinct families of the SIMIBI (after signal recognition particle, MinD and BioD) class of phosphate-binding loop NTPases. The genomic context and the partners identified for the archaeal and eukaryotic homologues indicate that they are involved in genome maintenance--DNA repair or replication. The crystal structure of PAB0955 from Pyrococcus abyssi shows that, unlike other SIMIBI class G proteins, these highly conserved GTPases are homodimeric, regardless of the presence of nucleotides. The nucleotide-binding site of PAB0955 is rather rigid and its conformation is closest to that of the activated SRP G domain. One insertion to the G domain bears a strictly conserved GPN motif, which is part of the catalytic site of the other monomer and stabilizes the phosphate ion formed. Owing to this unique functional feature, we propose to call this family as GPN-loop GTPase. Structural insights into a new homodimeric self-activated GTPase family.,Gras S, Chaumont V, Fernandez B, Carpentier P, Charrier-Savournin F, Schmitt S, Pineau C, Flament D, Hecker A, Forterre P, Armengaud J, Housset D EMBO Rep. 2007 Jun;8(6):569-75. Epub 2007 Apr 20. PMID:17468740[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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