Figure : A The binding of PI5P (1) and PI5P-diazirine (9) to recombinant hUHRF1 (200 nM) was analyzed using MST. Fracdon bound was ploked as an average of three independent measurements. Error bars correspond to the standard deviadon. The Kd value of PI5Pdiazirine (9) could not be determined due to the dtradon curve not reaching saturadon, however, a binding interacdon was observed at higher concentradons; B A cartoon depicdon of the workflow used to visualise PI5P (9) labelled hUHRF1, and other PI5P binding partners; C demonstrates the photo cross-linking of PI5P-diazirine (9) to purified recombinant hUHRF1 and hTAF3; D demonstrates the specificity of the photo cross-linking of PI5P-diazirine (9) to its binding partners, as it shows likle cross-linking to Bovine Serum Albumin (BSA). For C and D, each SDS-PAGE gel was analysed for fluorescence emiked by a TAMRA-azide dye, which was conjugated to the alkyne funcdonality of probe 9 via 'click' chemistry, using the appropriate filters for excitadon at 546 nm and emission at 579 nm (lep panel), total protein in each lane was observed via Coomassie staining (right panel). UV irradiadon refers to the lysate/sample being exposed to 365 nm UV light for 30 min, which is necessary for photo-crosslinking of PI5P diazirine (9) to bound proteins.