Ribosomal History Reveals Origins of Modern Protein Synthesis (original) (raw)
Figure 7
Model of ribosomal evolution.
A chronological representation of the evolution of the ribosome shows that very early in ribosomal evolution (nd<0.3) rRNA helices interacted with r-proteins to form a processivity core that mediated nucleotide interactions, which later (nd = 0.3) served as center for coordinated and balanced RNP accretion leading to modern ribosomal function. The purple structure indicates extant mRNA, which is used as structural reference for location of primitive functional centers. We envision the primordial ribosome had replicative functions that likely involved RNA, so the mRNA molecule from the crystallographic model should be regarded as placeholder for the ancient coding molecule. rRNA is rendered as ribbon representation, mRNA and proteins as rendered as space-filling representations.