what is the sequence to left AUG called why is the TATA box

what is the sequence to left AUG called

why is the TATA box and the TATAAT of A_T bases, how does it help seperate the two strands dna

if we were to add more than a, t, g, c, bases to the sequence what proteins or-and enzymes would change.-

Solution

The condon AUG is the start codon for transcription and represents the codon number 1 from the linear order of a gene. Left side or upstream the start codon, one can see an evolutionarily conserved consensus sequence of nitrogenous bases atleast 10 bp before AUG. This sequence is the TATAAT or TATA and named as \"TATA box\". Importantly, upstream to TATA box, there occurs more consensus sequences located 35-70 bp upstream the start codon.

Significance of these sequences: These consensus and conserved sequences represent the identification and binding sites for RNA polymerase so that transcription could be performed at appropriate position.

Secondarily, if the TATA bases are changed with more A,T,C or G bases, the consensus of this preserved sequence would be lost and RNA polymerase would not be able to identify and bind to start site. Similarly, it will also result in failure of strand separation because when RNA polymerase would not bind, the transcription will not start and hence, helicase will not start strand opening.