The exosome complex contains two catalytic subunits which degrade RNA in either a distributive (Rrp6) or a processive (Rrp44) manner—previous structures indicated how RNA could be directed to Rrp44, but the path taken to Rrp6 was unclear; here the location of the Rrp6 catalytic domain and the RNA 3′ end are determined and it is found that the RNA lies in an opposite orientation from that of the Rrp44-containing exosome structure, suggesting that the fate of an RNA may be influenced by the manner in which cofactors present it.
- Elizabeth V. Wasmuth
- Kurt Januszyk
- Christopher D. Lima