Building Upon Local Alignmentsclick to expand

We have thus far worked with local alignments with a linear gap penalty and global alignments with affine gap penalties (see “Local Alignment with Scoring Matrix” and “Global Alignment with Scoring Matrix and Affine Gap Penalty”).

It is only natural to take the intersection of these two problems and find an optimal local alignment given an affine gap penalty.

Problem

Given: Two protein strings $s$ and $t$ in FASTA format (each having length at most 10,000 aa).

Return: The maximum local alignment score of $s$ and $t$, followed by substrings $r$ and $u$ of $s$ and $t$, respectively, that correspond to the optimal local alignment of $s$ and $t$. Use:

• The BLOSUM62 scoring matrix.
• Gap opening penalty equal to 11.
• Gap extension penalty equal to 1.

If multiple solutions exist, then you may output any one.

Sample Dataset

>Rosalind_8
PLEASANTLY
>Rosalind_18
MEANLY

Sample Output

12
LEAS
MEAN