Specificity determinants in phosphoinositide dephosphorylation: crystal structure of an archetypal inositol polyphosphate 5-phosphatase.
Tsujishita, Y., Guo, S., Stolz, L.E., York, J.D., Hurley, J.H.(2001) Cell 105: 379-389
- PubMed: 11348594 
- DOI: https://doi.org/10.1016/s0092-8674(01)00326-9
- Primary Citation of Related Structures:  
1I9Y, 1I9Z - PubMed Abstract: 
Inositol polyphosphate 5-phosphatases are central to intracellular processes ranging from membrane trafficking to Ca(2+) signaling, and defects in this activity result in the human disease Lowe syndrome. The 1.8 resolution structure of the inositol polyphosphate 5-phosphatase domain of SPsynaptojanin bound to Ca(2+) and inositol (1,4)-bisphosphate reveals a fold and an active site His and Asp pair resembling those of several Mg(2+)-dependent nucleases. Additional loops mediate specific inositol polyphosphate contacts. The 4-phosphate of inositol (1,4)-bisphosphate is misoriented by 4.6 compared to the reactive geometry observed in the apurinic/apyrimidinic endonuclease 1, explaining the dephosphorylation site selectivity of the 5-phosphatases. Based on the structure, a series of mutants are described that exhibit altered substrate specificity providing general determinants for substrate recognition.
Organizational Affiliation: 
Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, , Bethesda, MD 20892, USA.