BQR-695(cas 1513879-21-4) is a PI4KIIIβ inhibitor with IC50s of 80 and 3.5 nM for human PI4KIIIβ and Plasmodium variant of PI4KIIIβ, respectively.
1. Protein Sci. 2016 Apr;25(4):826-39. doi: 10.1002/pro.2879. Epub 2016 Feb 1.
Using hydrogen deuterium exchange mass spectrometry to engineer optimized
constructs for crystallization of protein complexes: Case study of PI4KIIIβ with
Fowler ML(1), McPhail JA(1), Jenkins ML(1), Masson GR(2), Rutaganira FU(3),
Shokat KM(3), Williams RL(2), Burke JE(1).
(1)Department of Biochemistry and Microbiology, University of Victoria, British
Columbia, V8P 5C2, Canada.
(2)MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge
Biomedical Campus, Cambridge, CB2 0QH, United Kingdom.
(3)Howard Hughes Medical Institute and Department of Cellular and Molecular
Pharmacology, University of California, San Francisco (UCSF), California, 94158.
The ability of proteins to bind and interact with protein partners plays
fundamental roles in many cellular contexts. X-ray crystallography has been a
powerful approach to understand protein-protein interactions; however, a
challenge in the crystallization of proteins and their complexes is the presence
of intrinsically disordered regions. In this article, we describe an application
of hydrogen deuterium exchange mass spectrometry (HDX-MS) to identify dynamic
regions within type III phosphatidylinositol 4 kinase beta (PI4KIIIβ) in complex
with the GTPase Rab11. This information was then used to design deletions that
allowed for the production of diffraction quality crystals. Importantly, we also
used HDX-MS to verify that the new construct was properly folded, consistent with
it being catalytically and functionally active. Structures of PI4KIIIβ in an Apo
state and bound to the potent inhibitor BQR695 in complex with both GTPγS and GDP
loaded Rab11 were determined. This hybrid HDX-MS/crystallographic strategy
revealed novel aspects of the PI4KIIIβ-Rab11 complex, as well as the molecular
mechanism of potency of a PI4K specific inhibitor (BQR695). This approach is
widely applicable to protein-protein complexes, and is an excellent strategy to
optimize constructs for high-resolution structural approaches.