Molecular details of the CPSF73-CPSF100 C-terminal heterodimer and interaction with Symplekin

Abstract

Eukaryotic pre-mRNA is processed by a large multiprotein cleavage and polyadenylation complex to accurately cleave the 3’ end, and to catalyze the addition of the poly(A) tail. Within the cleavage and polyadenylation specificity factor (CPSF) machinery, the CPSF73 endonuclease subunit directly contacts both CPSF100 and the scaffold protein Symplekin to form a stable subcomplex known also as the core cleavage complex (CCC) or mammalian cleavage factor (mCF). Here we have taken advantage of a stable CPSF73-CPSF100 minimal complex fromE. cuniculito determine the solution structure of the folded complex formed by the first and second C-terminal domain (CTD1 and CTD2) of both proteins. We find a large number of contacts between both proteins in the complex, and notably in the region between CTD1 and CTD2. A previously unreported similarity is also evident between CTD2 and the TATA-box binding protein (TBP) domains. Separately, we have determined the structure of the terminal CTD3 domain of CPSF73, which also belongs to the TBP domain family and is connected by a flexible linker to the rest of CPSF73. Biochemical assays demonstrate a key role for the CTD3 of CPSF73 in the recognition of Symplekin, and structural models of the trimeric complex from other species allow for comparative analysis and support an overall conserved architecture.

A cutting plane approach to maximization of fundamental frequency in truss topology optimization

“…Similarly, condition (16) tells us that equilibrium is attained for all load cases and the strain energy never surpasses γ.…”

“…The solution of (P ), given by CPAS, PENLAB, and FMINSDP, is compared. We install PENLAB from [15] and FMINSDP from [16]. Default installation parameters and settings in both solvers are employed.…”