Journal Article

FZJ-2020-00884

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Biochemical and structural characterization of murine GBP7, a guanylate binding protein with an elongated C-terminal tail

Legewie, L. ; Loschwitz, J.FZJ* ; Steffens, N. ; Prescher, M. ; Wang, X.FZJ* ; Smits, S. H. J. ; Schmitt, L. ; Strodel, B.FZJ* ; Degrandi, D. (Corresponding author) ; Pfeffer, K. (Corresponding author)

2019
Portland Press79505 London

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Please use a persistent id in citations: http://hdl.handle.net/2128/24243  doi:10.1042/BCJ20190364

Abstract: Guanylate-binding proteins (GBPs) constitute a family of interferon-inducible guanosine triphosphatases (GTPases) that are key players in host defense against intracellular pathogens ranging from protozoa to bacteria and viruses. So far, human GBP1 and GBP5 as well as murine GBP2 (mGBP2) have been biochemically characterized in detail. Here, with murine GBP7 (mGBP7), a GBP family member with an unconventional and elongated C-terminus is analyzed. The present study demonstrates that mGBP7 exhibits a concentration-dependent GTPase activity and an apparent GTP turnover number of 20 min-1. In addition, fluorescence spectroscopy analyses reveal that mGBP7 binds GTP with high affinity (KD = 0.22 µM) and GTPase activity assays indicate that mGBP7 hydrolyzes GTP to GDP and GMP. The mGBP7 GTPase activity is inhibited by incubation with γ-phosphate analogs and a K51A mutation interfering with GTP binding. SEC-MALS analyses give evidence that mGBP7 forms transient dimers and that this oligomerization pattern is not influenced by the presence of nucleotides. Moreover, a structural model for mGBP7 is provided by homology modeling, which shows that the GTPase possesses an elongated C-terminal (CT) tail compared with the CaaX motif-containing mGBP2 and human GBP1. Molecular dynamics simulations indicate that this tail has transmembrane characteristics and, interestingly, confocal microscopy analyses reveal that the CT tail is required for recruitment of mGBP7 to the parasitophorous vacuole of Toxoplasma gondii.

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Contributing Institute(s):

1. Strukturbiochemie (ICS-6)
2. JARA - HPC (JARA-HPC)

Research Program(s):

1. 551 - Functional Macromolecules and Complexes (POF3-551) (POF3-551)
2. Structural dynamics of murine guanylate binding proteins, their dimerization and interaction with lipid bilayers (jics6a_20190501) (jics6a_20190501)

Appears in the scientific report 2019

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