An alternate conformation and a third metal in PstP/Ppp, the M. tuberculosis PP2C-Family Ser/Thr protein phosphatase.
Serine/threonine protein phosphatases are central mediators of phosphorylation-dependent signals in eukaryotes and a variety of pathogenic bacteria. Here, we report the crystal structure of the intracellular catalytic domain of Mycobacterium tuberculosis PstPpp, a membrane-anchored phosphatase in the PP2C family. Despite sharing the fold and two-metal center of human PP2Calpha, the PstPpp catalytic domain binds a third Mn(2+) in a site created by a large shift in a previously unrecognized flap subdomain adjacent to the active site. Mutations in this site selectively increased the Michaelis constant for Mn(2+) in the reaction of a noncognate, small-molecule substrate, p-nitrophenyl phosphate. The PstP/Ppp structure reveals core functional motifs that advance the framework for understanding the mechanisms of substrate recognition, catalysis, and regulation of PP2C phosphatases.
Pullen
Kristi E
KE
Department of Molecular and Cell Biology, 339 Hildebrand Hall #3206, University of California, Berkeley, Berkeley, CA 94720, USA.
Ng
Ho-Leung
HL
Sung
Pei-Yi
PY
Good
Matthew C
MC
Smith
Stephen M
SM
Alber
Tom
T
D000595:Amino Acid Sequence; D020134:Catalytic Domain; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009169:Mycobacterium tuberculosis / Q000201:enzymology*; D010749:Phosphoprotein Phosphatases / Q000737:chemistry* / Q000378:metabolism; D011487:Protein Conformation; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity
D010749:Phosphoprotein Phosphatases