Ribosome recycle For elongation For initiation Termination Dissociation of Ribosomes Reinitiation initiation factots(IF) IFl and IF3 take part in ribosome dissociation HH HLLL 100 'oo 'He'vy 50 20 30 40 50 Fraction number
Ribosome recycle For elongation For initiation Dissociation of Ribosomes IFl and IF3 take part in ribosome dissociation initiation factots(IF)
70s50 30S 0.8 (a) No factors 0.6 0.4 IF3 cause dissociation of 02 70S into 30S and 50S subunits 08 709509309 (b) IF1(14g) 06 02 70S 50S 08 303 (c) IF3(2.6ug) 0.6 Figure 17.5 Effect of 04 IF3 in dissociating ribosomes 02 Fraction number
IF3 cause dissociation of 70S into 30S and 50S subunits Figure 17.5 Effect of IF3 in dissociating ribosomes
IF-3 binds to the free 30s subunits 5000 70S63S50S 30S 70S 50S B08 IF-3 ↓↓↓ 1.0 4000 E 0.8 Ribosome without IF-3 3000 白 0.6 Ribosome with IF-3 2000 22 pmol 109 pmol 0.4 1000 0.2 0 12 16 0 4 8 12 6 Figure 17.6 raction number
IF-3 binds to the free 30S subunits Ribosome without IF-3 Ribosome with IF-3 22 pmol 109 pmol IF-3
IF-1 promotes dissociation Rate limiting step Dissociation (slow) Association (fast) Exchange ratio +factors 6 With factors (IF-1) 5 100 without 0 3 60 2 40 89 20 20 40 60 80 100 Incubation time(min)
IF-1 promotes dissociation +factors Rate limiting step With factors (IF-1) without Exchange ratio
The role of IF-1 and IF-3 in ribosome dissociation CopyrightThe McGraw-Hill Companies,Permission required for reproduction or display. Figure 17.7 No reassociation Dissociation IF-3
17.7 The role of IF-1 and IF-3 in ribosome dissociation