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Structure of Streptococcus agalactiae serine/threonine phosphatase
Author(s) -
Rantanen Mika K.,
Lehtiö Lari,
Rajagopal Lakshmi,
Rubens Craig E.,
Goldman Adrian
Publication year - 2007
Publication title -
the febs journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 204
eISSN - 1742-4658
pISSN - 1742-464X
DOI - 10.1111/j.1742-4658.2007.05845.x
Subject(s) - serine , chemistry , threonine , binding site , active site , hydrolase , molecular replacement , crystal structure , crystallography , stereochemistry , phosphatase , protein structure , monomer , metal , enzyme , biochemistry , organic chemistry , polymer
We solved the crystal structure of Streptococcus agalactiae serine/threonine phosphatase (SaSTP) using a combination of single‐wavelength anomalous dispersion phasing and molecular replacement. The overall structure resembles that of previously characterized members of the PPM/PP2C STP family. The asymmetric unit contains four monomers and we observed two novel conformations for the flap domain among them. In one of these conformations, the enzyme binds three metal ions, whereas in the other it binds only two. The three‐metal ion structure also has the active site arginine in a novel conformation. The switch between the two‐ and three‐metal ion structures appears to be binding of another monomer to the active site of STP, which promotes binding of the third metal ion. This interaction may mimic the binding of a product complex, especially since the motif binding to the active site contains a serine residue aligning remarkably well with the phosphate found in the human STP structure.