Figure 5.

The Mbb1 protein is part of a 300-kDa complex associated with RNA. Soluble cell extracts or polysome extracts from the Mbb1∷HA strain, prepared as described (Materials and Methods), were fractionated by size-exclusion chromatography. The 28 50-μl fractions were collected, and each fraction was analyzed by SDS/PAGE and immunoblotting with anti-HA antibodies (rows 1, 3, 5, 6, and 8), by antibodies against RbcL (rows 10–12), or by RNA blotting with probes specific for the 16S rRNA (rows 2, 4, 7, and 9) and psbB genes (row 13). Because the psbB RNA was slightly degraded under the conditions used, a slot blot hybridization was performed. Size standards were used to calibrate the column as indicated.