Size-exclusion chromatography of soluble chloroplast proteins from Nicotiana tabacum (tobacco)

Maturase K (MatK) is the only splicing factor encoded in the chloroplast genomes of land plants. Here we used a transplastomic Nicotiana tabacum line, in which the plastidial MatK gene is C-terminally tagged with a 3x-HA tag, to conduct size-exclusion chromatography of soluble protein extracts enriched for chloroplast proteins. Fractions 5 and 6, in which MatK-HA was found most abundant by western blot analysis, were subjected to mass spectrometry analysis.