Fig. 8. The N-terminal region of M31 contains a nuclear envelope-binding site. (A) Schematic representation of the M31 mutants used in these experiments. The positions of the peptides relative to CD and CSD are indicated. (B) Purified proteins used in competition assays after SDS–PAGE and Coomassie Blue staining. M, molecular weight markers with the indicated molecular masses. (C) Sequence and mass spectra profile of the synthetic peptide M31NP, which was too small for analysis in regular SDS gels. (D and E) Competition of [³⁵S]GST–M31 binding by various M31 mutants, GST and BSA (controls). All assays presented here were done in duplicate with ∼1 µM radiolabeled probe. Variation of data points was <10%.