Coevolutionary signal in myoglobin at ( i , i + n ) pairs for n ranging from 1 to 20. -log(p-values) are presented for each separation of n residues (i, i + n) for n ranging from 1 to 20. Biochemical studies of alpha helices suggest that a statistically significant signal should be detectable at (i, i + 3) and (i, i + 4). Black digits indicate values of n significant at α = 0.05, and red digits indicate values of n significant after Bonferroni adjustment for multiple comparisons, α = 0.0025. Each graph (A-J) represents performance with a different algorithm. Where applicable, alignments were recoded with the CHARGE_HIS_2 alphabet, which consistently yielded among the best results. When recoding with CHARGE_HIS_2 was not applicable, LnLCorr and CoMap, the DEF99 and ORIG data sets (respectively) are presented.