title: Refined structures of placental alkaline phosphatase show a consistent pattern of interactions at the peripheral site.
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.
authors.affiliation: Sanford-Burnham Medical Research Institute, La Jolla, CA 92037, USA. bstec@burnham.org
authors.forename: Boguslaw
authors.initials: B
authors.lastname: Stec
authors.forename: Anton
authors.initials: A
authors.lastname: Cheltsov
authors.forename: José Luis
authors.initials: JL
authors.lastname: Millán
mesh_terms: D000469:Alkaline Phosphatase / Q000737:chemistry*; D018360:Crystallography, X-Ray; D005260:Female; D006801:Humans; D008958:Models, Molecular; D010920:Placenta / Q000201:enzymology*; D011247:Pregnancy; D054730:Protein Interaction Domains and Motifs; D020836:Protein Structure, Quaternary
chemical_list: D000469:Alkaline Phosphatase