Reference - PMID:19026779 - The structure of Fcp1, an essential RNA polymerase II CTD phosphatase.
Reference summary
- PubMed ID
- PMID:19026779
- Title
- The structure of Fcp1, an essential RNA polymerase II CTD phosphatase.
- Authors
- Ghosh A, Shuman S, Lima CD
- Citation
- Mol Cell 2008 Nov 21;32(4):478-90
- Publication year
- 2008
- Abstract
- Kinases and phosphatases regulate mRNA synthesis and processing by phosphorylating and dephosphorylating the C-terminal domain (CTD) of the largest subunit of RNA polymerase II. Fcp1 is an essential CTD phosphatase that preferentially hydrolyzes Ser2-PO(4) of the tandem YSPTSPS CTD heptad array. Fcp1 crystal structures were captured at two stages of the reaction pathway: a Mg-BeF(3) complex that mimics the aspartylphosphate intermediate and a Mg-AlF(4)(-) complex that mimics the transition state of the hydrolysis step. Fcp1 is a Y-shaped protein composed of an acylphosphatase domain located at the base of a deep canyon formed by flanking modules that are missing from the small CTD phosphatase (SCP) clade: an Fcp1-specific helical domain and a C-terminal BRCA1 C-terminal (BRCT) domain. The structure and mutational analysis reveals that Fcp1 and Scp1 (a Ser5-selective phosphatase) adopt different CTD-binding modes; we surmise the CTD threads through the Fcp1 canyon to access the active site.
