Molecular model of the RNA exosome core from C. thermophilum. It consists of Rrp45 (orange), an exoribonuclease phosphorolytic domain-containing protein (cyan), an exoribonuclease-like protein (yellow-green), an exoribonuclease phosphorolytic domain-containing protein (dark blue), an exoribonuclease phosphorolytic domain-containing protein (brown), the exosome complex component MTR3 (dark cyan), the ribosomal RNA-processing protein 40 (green), the putative exosome complex protein (pink) and the putative exosome 3->5 protein (not visible).