6.3 Initiation in bacteria needs 30S subunits and accessory factors Initiation factors (IF in prokaryotes,elF in eukaryotes)are proteins that associate with the small subunit of the ribosome specifically at the stage of initiation of protein synthesis 情莘大学
Initiation factors (IF in prokaryotes, eIF in eukaryotes) are proteins that associate with the small subunit of the ribosome specifically at the stage of initiation of protein synthesis. 6.3 Initiation in bacteria needs 30S subunits and accessory factors
6.3 Initiation in bacteria Initiation factors needs 30S subunits and accessory factors Figure 6.8 Initiation requires free 30S subunits Separate Pool of free ribosome subunits.When with initi ation subunits ribosomes factors ribosomes are released at termination,they dissociate to generate free subunits.Initiation factors are present only on dissociated 30S subunits.When subunits reaassociate to give a functional ribosome at initiation, they release the factors. Initiation Elongation Termination 清菜大当
Figure 6.8 Initiation requires free ribosome subunits. When ribosomes are released at termination, they dissociate to generate free subunits. Initiation factors are present only on dissociated 30S subunits. When subunits reaassociate to give a functional ribosome at initiation, they release the factors. 6.3 Initiation in bacteria needs 30S subunits and accessory factors
Bind ribosome to initi ation site 6.3 Initiation in AUG on mRNA bacteria needs Add nuclease 30S subunits and to digest all unprotected accessory factors -AUG mRNA Isolate -AUG- fragment of protected mRNA Figure 6.15 Ribosome- Determine sequence of binding sites on mRNA AACA GGAGGAUUACCCCAUGUCGAAGCAA protected Leader Coding region fragment can be recovered from initiation complexes All initi ation Shine-Dalgarno AUG regions have <10 bases in center of two consensus upstream of AUG protected elements fragment 清菜大当
Figure 6.15 Ribosomebinding sites on mRNA can be recovered from initiation complexes. 6.3 Initiation in bacteria needs 30S subunits and accessory factors
Initiation requires factors and free subunits 6.3 Initiation in bacteria needs 30S subunits and accessory factors Figure 6.9 Initiation factors stabilize free 30S subunits and bind initiator tRNA to the 30S-mRNA complex. 1F-3 清苇大当
Figure 6.9 Initiation factors stabilize free 30S subunits and bind initiator tRNA to the 30S-mRNA complex. 6.3 Initiation in bacteria needs 30S subunits and accessory factors
Free Pool of 70S subunits ribosomes Dynamic 6.3 Initiation in equilibrium 1F-3 bacteria needs 30S subunits and accessory factors 30S subunit with IF-3 can bind mRNA cannot bind 50S subunit Figure 6.10 Initiation requires 30S subunits IF-3 must be released that carry IF-3. before 50S subunit can join 情莘大兰
Figure 6.10 Initiation requires 30S subunits that carry IF-3. 6.3 Initiation in bacteria needs 30S subunits and accessory factors