Am. Baptista et al., THE ORIGIN OF TRYPSIN - EVIDENCE FOR MULTIPLE GENE DUPLICATIONS IN TRYPSINS, Journal of molecular evolution, 47(3), 1998, pp. 353-362
The trypsin family of serine proteases is one of the most studied prot
ein families, with a wealth of amino acid sequence information availab
le in public databases. Since trypsin-like enzymes are widely distribu
ted in living organisms in nature, likely evolutionary scenarios have
been proposed. A novel methodology for Fourier transformation of biolo
gical sequences (FOTOBIS) is presented. The methodology is well suited
for the identification of the size and extent of short repeats in pro
tein sequences. In the present paper the trypsin family of enzymes is
analyzed with FOTOBIS and strong evidence for tandem gene duplication
is found. A likely evolutionary path for the development of present-da
y trypsins involved an intrinsic extensive tandem gene duplication of
a small DNA fragment of 15-18 nucleotides, corresponding to five or si
x amino acids. This ancestral trypsin gene was subsequently duplicated
, leading to the earliest version of a full-sized trypsin, from which
the contemporary trypsins have developed.