Novel Dihydropteridinone Derivatives As Potent Inhibitors of the Understudied Human Kinases Vaccinia-Related Kinase 1 and Casein Kinase 1δ/ε.

Vaccinia-related kinase 1 (VRK1) and the δ and ε isoforms of casein kinase 1 (CK1) are linked to various disease-relevant pathways. However, the lack of tool compounds for these kinases has significantly hampered our understanding of their cellular functions and therapeutic potential. Here, we describe the structure-based development of potent inhibitors of VRK1, a kinase highly expressed in various tumor types and crucial for cell proliferation and genome integrity. Kinome-wide profiling revealed that our compounds also inhibit CK1δ and CK1ε. We demonstrate that dihydropteridinones 35 and 36 mimic the cellular outcomes of VRK1 depletion. Complementary studies with existing CK1δ and CK1ε inhibitors suggest that these kinases may play overlapping roles in cell proliferation and genome instability. Together, our findings highlight the potential of VRK1 inhibition in treating p53-deficient tumors and possibly enhancing the efficacy of existing cancer therapies that target DNA stability or cell division.

Expression, purification, crystallization and preliminary X-ray diffraction analysis of Bifidobacterium adolescentis xylose isomerase.

Xylose isomerase (EC 5.3.1.5) is a key enzyme in xylose metabolism which is industrially important for the transformation of glucose and xylose into fructose and xylulose, respectively. The Bifidobacterium adolescentis xylA gene (NC_008618.1) encoding xylose isomerase (XI) was cloned and the enzyme was overexpressed in Escherichia coli. Purified recombinant XI was crystallized using the sitting-drop vapour-diffusion method with polyethylene glycol 3350 as the precipitating agent. A complete native data set was collected to 1.7 Šresolution using a synchrotron-radiation source. The crystals belonged to the orthorhombic space group P21212, with unit-cell parameters a = 88.78, b = 123.98, c = 78.63 Å.