B Sequence alignment of the first 62 residues of USP45 from the indicated species. Conserved residues that were mutated in part (C) are indicated in red. The residues whose mutation in (C) is shown to inhibit binding to ERCC1 are marked with an asterisk. Residue Thr37 (marked with a solid triangle) was found to destabilise expression when mutated to Ala. 