Fig. 1

Sequence analysis and flexibility mapping of the INPP5K catalytic domain. (A) Structural model of human INPP5K-cd, generated using Boltz-2¹², highlighting the predicted flexible loop region (magenta) corresponding to the sequence indicated in (B). (B) Sequence alignment showing the insertion region unique to INPP5K among human IP5Pases. (C) Sequence variations in the predicted loop region among human, mouse, and rat INPP5K. Residues differing from the human sequence are shown in red. The region targeted for substitution is indicated by the red dotted line. (D) Heat maps display the mean % deuteration of fragments of human INPP5K-cd. Each color block represents an analyzed peptide fragment. The deuteration levels of peptides are differently colored as blocks in the insert at six time points (15, 50, 150, 500, 1 500 and 5 000 s). The colors of the double-headed arrows correspond to those used in the structure model in E. The green arrow and blue arrows indicate the alpha-helix and beta-sheets, respectively. The predicted loop fragment is shown in a square magenta box. The predicted flexible loop fragment (residues 276–293) is boxed in magenta. (E) Ribbon diagram of the INPP5K-cd structural model, colored according to the results of the HDX–MS analysis. The central beta-sheet core is shown in blue, the major alpha-helix in green, and the predicted flexible loop (residues 276–293) in magenta. Other structural elements, including the connecting loops and smaller helices, are shown in orange.