X-Ray Analysis of Prokaryotic and Eukaryotic Ribosomes - Biophysical Approaches to Translational Control of Gene Expression - page 19

b

a

40S

40S head

head

body

60S

60S

d

c

Eukaryotic ratcheted state

Prokaryotic unratcheted state

30S head

40S head

h33 h33

S13p

S19p

S18

S15

B1b

B1a

B1b

L11

ASF B1a

L5p

ASF 50S

60S

f

e

S18

h33

B1b B1b

S15

B1a

L11

ASF

L11

Fig. 1.9 Ratcheted state of the eukaryotic 80S ribosome. ( a , b ) Schematic representation of the
motion from the unratcheted to the ratcheted state. The red line indicates the outline of the 40S in
the unratcheted state, with arrows indicating the trajectory. ( a ) Top view of the yeast 80S ribosome.