The 1.35 A resolution structure of the phosphatase domain of the suppressor of T-cell receptor signaling protein in complex with sulfate.
The suppressor of T-cell signaling (Sts) proteins are multidomain proteins that negatively regulate the signaling of membrane-bound receptors, including the T-cell receptor (TCR) and the epidermal growth-factor receptor (EGFR). They contain at their C-terminus a 2H-phosphatase homology (PGM) domain that is responsible for their protein tyrosine phosphatase activity. Here, the crystal structure of the phosphatase domain of Sts-1, Sts-1(PGM), was determined at pH 4.6. The asymmetric unit contains two independent molecules and each active site is occupied by a sulfate ion. Each sulfate is located at the phosphate-binding site and makes similar interactions with the catalytic residues. The structure suggests an explanation for the lower Michaelis-Menten constants at acidic pH.
Jakoncic
Jean
J
Brookhaven National Laboratory, National Synchrotron Light Source, Building 725, Upton, NY 11973, USA.
Sondgeroth
Benjamin
B
Carpino
Nick
N
Nassar
Nicolas
N
D000818:Animals; D018360:Crystallography, X-Ray; D006863:Hydrogen-Ion Concentration; D051379:Mice; D008958:Models, Molecular; D010744:Phosphoric Monoester Hydrolases / Q000737:chemistry* / Q000378:metabolism; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D017027:Protein Tyrosine Phosphatases; D011948:Receptors, Antigen, T-Cell / Q000737:chemistry* / Q000378:metabolism; D013431:Sulfates / Q000737:chemistry* / Q000378:metabolism
D011948:Receptors, Antigen, T-Cell; D013431:Sulfates; D010744:Phosphoric Monoester Hydrolases; D017027:Protein Tyrosine Phosphatases; C553497:TULA-2 protein, mouse