5o74
From Proteopedia
Crystal structure of human Rab1b covalently bound to the GEF domain of DrrA/SidM from Legionella pneumophila in the presence of GDP
Structural highlights
FunctionDRRA_LEGPN Virulence effector that plays a key role in hijacking the host vesicular trafficking by recruiting the small guanosine triphosphatase (GTPase) Rab1 to the cytosolic face of the Legionella-containing vacuole (LCVs). Acts as a GDP-GTP exchange factor (GEF) for the small GTPase Rab1 (RAB1A, RAB1B or RAB1C), thereby converting Rab1 to an active GTP-bound state, leading to the incorporation of Rab1 into LCVs. Also shows RabGDI displacement factor (GDF) activity; however, this probably represents a passive activity following the GEF activity. Also acts as an adenylyltransferase by mediating the addition of adenosine 5'-monophosphate (AMP) to 'Tyr-77' of host RAB1B, thereby rendering RAB1B constitutively active. Also has adenylyltransferase activity towards Rab6 and Rab35. Also displays guanylyltransferase activity by mediating the addition of guanosine 5'-monophosphate (GMP) to host RAB1B in vitro; however such activity remains uncertain in vivo. Specifically binds phosphatidylinositol 4-phosphate (PtdIns(4)P) lipids on the cytosolic surface of the phagosomal membrane shortly after infection.[1] [2] [3] Publication Abstract from PubMedThe characterization of low-affinity protein complexes is challenging due to their dynamic nature. Here we present a method to stabilize transient protein complexes in vivo by generating a covalent and conformationally flexible bridge between the interaction partners. A highly active pyrrolysyl tRNA synthetase mutant directs the incorporation of unnatural amino acids bearing bromoalkyl moieties (BrCnK) into proteins. We demonstrate for the first time that low-affinity protein complexes between BrCnK-containing proteins and their binding partners can be stabilized in vivo in bacterial and mammalian cells. Using this approach we determined the crystal structure of a transient GDP-bound complex between a small G-protein and its nucleotide exchange factor. We envision that this approach will prove valuable as a general tool for validating and characterizing protein-protein interactions in vitro and in vivo. Proximity-triggered covalent stabilization of low-affinity protein complexes in vitro and in vivo.,Cigler M, Muller TG, Horn-Ghetko D, von Wrisberg MK, Fottner M, Goody RS, Itzen A, Muller MP, Lang K Angew Chem Int Ed Engl. 2017 Sep 28. doi: 10.1002/anie.201706927. PMID:28960788[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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