Thermodynamics and Kinetics of Central Domain Assembly (original) (raw)

1. M.I. RECHT and
2. J.R. WILLIAMSON
3. Department of Molecular Biology and the Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, California 92037

Excerpt

The in vitro reconstitution of the 30S ribosomal subunitfrom Escherichia coli has served as the paradigm forstudies of the assembly of large ribonucleoprotein complexes ever since Nomura and colleagues demonstratedthat purified ribosomal proteins and 16S rRNA couldspontaneously form a functional 30S subunit. Initial studies with partially fractionated sets of ribosomal proteins(Traub and Nomura 1968, 1970), and later, experimentsmonitoring the binding of individually purified proteinsor specific mixtures of proteins to 16S rRNA, allowed thedevelopment of an assembly map for the in vitro reconstitution of the E. coli 30S subunit (Fig. 1) (Mizushimaand Nomura 1970; Nomura et al. 1970; Held et al. 1973,1974). The assembly map reveals a hierarchy to the binding of ribosomal proteins to form the 30S subunit. Thebinding of the ribosomal proteins can be divided intothree classes: primary, secondary, and tertiary bindingproteins. The primary binding proteins (S4, S7, S8, S15,S17, and S20) can bind directly to 16S rRNA in the absence of any other ribosomal proteins. Secondary bindingproteins (S5, S6, S9, S12, S13, S16, S18, and S19) require the prior binding of one of the primary binding proteins. Tertiary binding proteins, including S2, S3, S10,S11, S14, and S21, require the prior binding of one ormore secondary binding proteins...