Exploring Assembly Energetics of the 30S Ribosomal Subunit Using an Implicit Solvent Approach

To explore the relationship between the assembly of the 30S ribosomal subunit and interactions among the constituent components, 16S RNA and proteins, relative binding free energies of the T. thermophilus 30S proteins to the 16S RNA were studied based on an implicit solvent model of electrostatic, nonpolar, and entropic contributions. The late binding proteins in our assembly map were found not to bind to the naked 16S RNA. The 5' domain early kinetic class proteins, on average, carry the highest positive charge, get buried the most upon binding to 16S RNA, and show the most favorable binding. Some proteins (S10/S14, S6/S18, S13/S19) have more stabilizing interactions while binding as dimers. Our computed assembly map resembles that of E. coli; however, the central domain path is more similar to that of A. aeolicus, a hyperthermophilic bacteria.