Refined structures of placental alkaline phosphatase show a consistent pattern of interactions at the peripheral site.
Stec, B., Cheltsov, A., Millan, J.L.(2010) Acta Crystallogr Sect F Struct Biol Cryst Commun 66: 866-870
- PubMed: 20693656 
- DOI: https://doi.org/10.1107/S1744309110019767
- Primary Citation of Related Structures:  
3MK0, 3MK1, 3MK2 - PubMed Abstract: 
In order to gain deeper insights into the functional sites of human placental alkaline phosphatase, the structures of the enzyme with the putative regulators L-Phe, pNPP and 5'-AMP [Llinas et al. (2005), J. Mol. Biol. 350, 441-451] were re-refined. Significant variations in ligand positioning and identity were found compared with the previous report. The multiple corrections to the model improved the phases and the electron-density maps, allowing the modeling of omitted side chains and multiple disordered residues. These improvements led to a change in the position of L-Phe at the peripheral binding site, which appeared to be reversed. The structure with pNPP contained only p-nitrophenol in three distinct sites, while the structure with 5'-AMP contained the p-nitrophenyl group in two of the sites instead of 5'-AMP. Comparison of the re-refined models shows a consistent pattern of interactions at the peripheral site.
Organizational Affiliation: 
Sanford-Burnham Medical Research Institute, La Jolla, CA 92037, USA. bstec@burnham.org