Generally arbitrarily selected neuraminidases and hemagglutinins are true positives but the above kind of pattern, a segment of approximately 9–23 residues with a score exceeding 100 and centered on tryptophan with the peak score, is not universal. Sometimes it is another hydrophobic residue. In a “haemaglutinin repeat-containing protein” of a yet to be fully classified micororganism Candidatus Kentron a tryptophan (W) with a score of 118 is slightly displaced from the central peak of 119 associated with a run of three glycines (G). It is two glutamate residues (E), negatively charged that are in the vicinity in the sequence that appear to perturb the usual central role of tryptophan. Similarly, a rat neuraminidase is of some interest in that the predicted sequence SLDHGHTW surrounds the glycine (G) with peak score 106 and terminates at tryptophan (W) with a score of 102. The tryptophan is, however, immediately followed by a glutamate (E).