Figure 1.

Isolation of CS1 protein with the 30S ribosomal subunit. The 30S ribosomal small subunit was isolated as described in Materials and Methods. The isolated complex was fractionated on a Superdex 200 size exclusion column and the elution profile monitored by absorption at 280 nm (A). The protein profile of the high molecular weight complex was analyzed by SDS–PAGE and CS1 protein by UV-crosslinking to psbA 5′-UTR RNA (B, lanes 1 and 2, respectively). The CS1 and S5 ribosomal proteins were identified by an immunoblot of the fraction with the corresponding specific antibodies (C, lanes 1 and 2, respectively).