Purification and characterization of recombinant MP. (A) Anion exchange chromatography. Conductivity, 13.2–71.4 mS; pH, 8.73–9.24. P1, P2, and P3, peaks 1, 2, and 3. (B) Chromatographic fractions 1–40. (Upper) Silver-stained SDS/PAGE gels; (Lower) Western blots detecting MP. Unheated samples were subjected to SDS/PAGE; Mr as in Fig. 1. (C) Absorption spectra of P1, P2, and P3. (D) Nuclease digestion. Ethidium bromide-stained 1% Tris/borate/EDTA (lanes 1–4) and 1.5% formaldehyde-agarose (lanes 5–12) gels. Lanes 1–4: pET3MP DNA; in DNaseI buffer only (lane 1), or RNaseA buffer only (lane 2); in buffer with DNaseI (lane 3), or RNaseA (lane 4). Lanes 5–8: TMV RNA; in DNaseI buffer only (lane 5), or RNaseA buffer only (lane 6); with DNaseI (lane 7), or RNaseA (lane 8). Lanes 9–12: concentrated P3; in DNaseI buffer only (lane 9), or RNaseA buffer only (lane 10); with DNaseI (lane 11), or RNaseA (lane 12). Standards, in kbp (DNA; Left) and kb (RNA; Right).