Phosphatase Superfamily Cys-based III

Phosphatase Classification: Superfamily Cys-based III

This superfamily has a unique fold, but shares the common CX5R catalytic motif with another two cysteine-based superfamilies, superfamily Cys-based I and superfamily Cys-based II.

The superfamily consists of two member families present in human low molecular weight PTP (LWMPTP) and SSU72. Although human LMWPTP and SSU72 exhibit low sequence identity (15%), the overall folds are very similar. The rmsd (root mean square deviation) of 1.7 Å when superimposing SSU72 (PDB ID: 3OMW) with LMWPTP (PDB ID: 1XWW) [1].

The subfamily has an additional member only present in prokaryotes, arsenate reductase (ArsC). It has low sequence identity with LMWPTP and SSU72, 19% between Golden Staph ArsC (PDB ID: 1LJL) and mouse LMWPTP (PDB ID: 2P4U), 16% between Golden Staph ArsC and fruit fly SSU72 (PDB ID: 3FMV). But, ArsC has very similar structure with LMWPTP as shown in SCOP database.

Reference

1. 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 |