Crystal structures and snapshots along the reaction pathway of human phosphoserine phosphatase.
Haufroid, M., Mirgaux, M., Leherte, L., Wouters, J.(2019) Acta Crystallogr D Struct Biol 75: 592-604
- PubMed: 31205021 
- DOI: https://doi.org/10.1107/S2059798319006867
- Primary Citation of Related Structures:  
6HYJ, 6HYY, 6Q6J - PubMed Abstract: 
The equilibrium between phosphorylation and dephosphorylation is one of the most important processes that takes place in living cells. Human phosphoserine phosphatase (hPSP) is a key enzyme in the production of serine by the dephosphorylation of phospho-L-serine. It is directly involved in the biosynthesis of other important metabolites such as glycine and D-serine (a neuromodulator). hPSP is involved in the survival mechanism of cancer cells and has recently been found to be an essential biomarker. Here, three new high-resolution crystal structures of hPSP (1.5-2.0 Å) in complexes with phosphoserine and with serine, which are the substrate and the product of the reaction, respectively, and in complex with a noncleavable substrate analogue (homocysteic acid) are presented. New types of interactions take place between the enzyme and its ligands. Moreover, the loop involved in the open/closed state of the enzyme is fully refined in a totally unfolded conformation. This loop is further studied through molecular-dynamics simulations. Finally, all of these analyses allow a more complete reaction mechanism for this enzyme to be proposed which is consistent with previous publications on the subject.
Organizational Affiliation: 
Namur Medicine and Drug Innovation Center, Namur Research Institute for Life Science (NAMEDIC-NARILIS), Department of Chemistry, Laboratoire de Chimie Biologique Structurale (CBS), University of Namur (UNamur), 61 Rue de Bruxelles, 5000 Namur, Belgium.