Now you learn its identity and its distance from the corresponding residue in the reference layer. In both layers, Deep View selects and highlights the aligned pairs that are identical. Scroll through the sequence alignment. The alpha and beta chains probably evolved by divergence from a common ancestral globin gene. The highlighted residues are those that have been conserved during this evolution.
Conserved residues are likely to be essential to protein function.
Now a larger number of pairs are selected. Find similar pairs in which both are positively charged, negatively charged, small, polar, or nonpolar. Mutations that replace one residue with one of similar properties, such as lysine replaced by arginine, are called conservative mutations. In the beta-chain sequence, the highlighted residues are those that are neither identical nor similar to those in the alpha chain. These residues may serve different functions in the two subunits, or their specific side chains may not be essential to the function of the chain.