Phosphatase Superfamily CC2
Phosphatase Classification: Fold CC2: Superfamily CC2
This superfamily has a unique fold, but shares the common CX5R catalytic motif with another two cysteine-based superfamilies, CC1 and CC3.
CC2 consists of two member families in human low molecular weight PTP (LWMPTP) and SSU72. Despite having only 15% sequence identity, human LMWPTP and SSU72 structures superimpose with an rmsd of 1.7 Å [1].
A third family, arsenate reductase (ArsC) [2], is only found in prokaryotes. While known to reduce arsenate to arsenite (a similar reaction to the phosphatase reaction), the B. subtilis gene also has in vitro phosphatase activity. A different phosphatase fold, CDC25/Rhodanese also has members in plants and yeast (ACR2) that are capable of arsenate reductase activity, highlighting the similarity of the protein phosphatase and arsenate reductase activities.
Phosphatase domain structure
The two families LWMPTP and SSU72 has a common fold.
The SSU72 family has a secondary structure combination of E1, H1, E2, E3, E4, H2, H3, H4, E5, H5, E6, H6, H7, E7.
The LWMPTP family has a secondary structure combination of E1, H1, E2, H4 (or H3), E5, H5, E6, H6.
References
- Zhang Y, Zhang M, and Zhang Y. Crystal structure of Ssu72, an essential eukaryotic phosphatase specific for the C-terminal domain of RNA polymerase II, in complex with a transition state analogue. Biochem J. 2011 Mar 15;434(3):435-44. DOI:10.1042/BJ20101471 |
- Bennett MS, Guan Z, Laurberg M, and Su XD. Bacillus subtilis arsenate reductase is structurally and functionally similar to low molecular weight protein tyrosine phosphatases. Proc Natl Acad Sci U S A. 2001 Nov 20;98(24):13577-82. DOI:10.1073/pnas.241397198 |
