3ef0

Publication Abstract from PubMed

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.

The structure of Fcp1, an essential RNA polymerase II CTD phosphatase.,Ghosh A, Shuman S, Lima CD Mol Cell. 2008 Nov 21;32(4):478-90. PMID:19026779^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.