Figure 1.

Sucrose-gradient sedimentation of in vitro-transcribed t30S subunits. Complexes were loaded on 10-ml 10–40% sucrose gradients in 20 mM Hepes (pH 7.5), 100 mM NH₄Cl, 30 mM MgCl₂, and 6 mM B-mercaptoethanol, centrifuged for 13 hr in a Beckman SW41 rotor at 35,000 rpm at 4° and scanned with an ISCO density gradient fractionator (Model 183). Complexes were monitored by A₂₆₀ (■). A trace amount of [³²P]pCp-labeled 30S subunits, used as marker, was monitored by Cerenkov counting (○).