CCR4 NOT Transcription Complex Subunit 6 Like Protein (CNOT6L)

CNOT6L, a human homologue of CCR4, by X-ray crystallography using the single-wavelength anomalous dispersion method. This first structure of a deadenylase belonging to the EEP family adopts a complete α/β sandwich fold typical of hydrolases with highly conserved active site residues similar to APE1. The active site of CNOT6L should recognize the RNA substrate through its negatively charged surface. In vitro deadenylase assays confirm the critical active site residues and show that the nuclease domain of CNOT6L exhibits full Mg²⁺-dependent deadenylase activity with strict poly(A) RNA substrate specificity. To understand the structural basis for poly(A) RNA substrate binding, crystal structures of the CNOT6L nuclease domain have also been determined in complex with AMP and poly(A) DNA.