Orientation of the central domains of KSRP and its implications for the interaction with the RNA targets

KSRP is a multi-domain RNA-binding protein that recruits the exosome-containing mRNA degradation complex to mRNAs coding for cellular proliferation and inflammatory response factors. The selectivity of this mRNA degradation mechanism relies on KSRP recognition of AU-rich elements in the mRNA 3′UTR, that is mediated by KSRP’s KH domains. Our structural analysis shows that the inter-domain linker orients the two central KH domains of KSRP—and their RNA-binding surfaces—creating a two-domain unit. We also show that this inter-domain arrangement is important to the interaction with KSRP’s RNA targets

The vaccinia virus DNA polymerase structure provides insights into the mode of processivity factor binding

The catalytic subunit E9 of the vaccinia virus DNA polymerase forms a functional polymerase holoenzyme by interacting with the heterodimeric processivity factor A20/D4. Here the authors present the structure of full-length E9 and show that an insertion within its palm domain binds A20, in a mode different from other family B polymerases