PMID: 15350217 , Related PDB ids: 1TPZ, 1TQ2, 1TQ4, 1TQ6, 1TQD

Authors:

Ghosh A, Uthaiah R, Howard J, Herrmann C, Wolf E

Title:

Crystal structure of IIGP1: a paradigm for interferon-inducible p47 resistance GTPases.

Journal:

Mol Cell. 2004 Sep 10;15(5):727-39.

Abstract:

Interferon-inducible p47 GTPases are critical mediators of cell-autonomous resistance against several intracellular pathogens. Here we present the first crystal structure of a member of this novel GTPase family, IIGP1, in its nucleotide-free, GDP-, and GppNHp-bound form. The structure shows a Ras-like G domain between an N-terminal three-helix bundle and a complex system of C-terminal helices and loops. Sequence comparison and secondary structure prediction suggest the IIGP1 structure to be a valid model for the p47 GTPase family. The IIGP1 crystals contain a noncrystallographic dimer. We show that the dimer is required for cooperative GTP hydrolysis and GTP-dependent oligomerization of IIGP1. We also present the GDP- and GppNHp-bound monomeric structures of two dimer interface mutants. Our structures direct approaches to the analysis of the catalytic mechanism of IIGP1 and provide a coherent basis for structure-function studies aimed at elucidating the mechanistic basis of pathogen resistance caused by these enigmatic GTPases.