IMG00208

Molccular model fpr attenuation fcpjitJ:

in attenuation:

Pgg/t/gn gf the r>t>ę>ggmg playg aa jmg^rtantigls

When    Trp Is scarce or In short supply (and requlred):

1.    Trp-tRNAs are unavailable, rlbosome stalls at Trp codons and

covers attenuator region 1.

2. Region 1 cannot pair with region 2, łnstead region 2 palrs włth region 3 when it is synthesized.

3. Region 3 (now paired with region 2) is unable to pair with region 4 when it is synthesized.

4. RNA    polymerasc continues transcribłng region 4 and beyond

synthesizing a completc trp mRNA.