Below is a list of the first 10 residues of the B helix in m

Below is a list of the first 10 residues of the B helix in myoglobin from different organisms.

Which positions can tolerate conservative substitution?

Hint: Which positions are mostly the same, with only an occasional substitution?

I tried position 1&8 but it was wrong

Position 78910 Human DIPGHGOEVL Chicken DIAGHGHEVL Alligator Turtle DLSAHGOEVI luna DYTTMGGLVL DFEGTGGEVL ILL-ILL 8EEEELE 7QHHQGG 4GGEATG 3PAPSTE 21-LLYF 1DDKDDD

Solution

The conservative substitution is tolerated if substitution is gained by amino acids of same group. In the given question only the 10^th order can tolerate the conservative substitution. It is because Isoleucine and leucine belongs to same family; aliphatic nonpolar group.