Question

The most common Class II variant is the F508del variant, which is missing the 508th amino acid in the protein but has an otherwise normal sequence. Loss of this amino acid leads to misfolding of the protein, and the misfolded protein is not properly transported to the membrane. Based on this information, how many nucleotides are deleted in the CFTR allele encoding this variant?

Answer 1

The correct answer is - 3 (two codons of 507th that are U, C, and the first nucleotide of 508th codon U).

Step-by-step explanation:

Each amino acid is coded by a three-nucleotide base long codon. So in the case of the F508del variant, there is a deletion of three nucleotides that is encoded for phenylalanine amino acid.

In this isoleucine is encoded by 507th codon that is AUG and 508th codon is UUU codes for Isoleucine.

In this case, two codons of 507th are U, C, and the first nucleotide of 508th codon U. So overall three nucleotides are deleted in the F508del variant..