Figure 5.

Dimerization does not increase total precursor binding to thylakoids. Thylakoids (20 μg chlorophyll) were incubated in a binding assay for 30 min with 1.3–60 μl of [³H] tOE17-20F or [³H] tOE17-20F3C precursor as indicated in lanes 2 through 8 and were subsequently washed twice before analysis. Lane 1 is an aliquot of translation product. (A) Samples were analysed by reducing SDS–PAGE to determine the total amount of precursor bound, which was quantified by scintillation counting of extracted gel bands (Cline, 1986) and plotted below the fluorogram. Total binding from the 60 μl tOE17-20F reaction was arbitrarily set at 100%. (B) Samples in (A) were analysed by non-reducing SDS–PAGE to determine the relative amounts of precursor dimer and monomer in each sample. The plot below the fluorogram depicts the dimer yield as a percentage of the total amount of precursor bound (i.e. dimer plus monomer).