  Protein-fragment seqlets typically feature about 10 amino acid residue
positions that are fixed to within conservative substitutions but usually
separated by a number of prescribed gaps with arbitrary residue content. By
quantifying a general amino acid residue sequence in terms of the associated
codon number sequence, we have found a precise modular Fibonacci sequence in a
continuous gap-free 10-residue seqlet with either 3 or 4 conservative amino
acid substitutions. This modular Fibonacci sequence is genuinely biophysical,
for it occurs nine times in the SWISS-Prot/TrEMBL database of natural proteins.
