In each column, the values are reported for the underlined species. It is now widely accepted that the present-day proteins descend from ancient building blocks, acquiring their complex architecture through the merging of primordial structural motifs and the addition of connective loops. The primordial motifs thus build the core of the proteins, and it is a common observation that the most conserved residues lie in the central parts of proteins while the most mutable amino acids are preferentially located in the intervening loops. We are currently trying to confirm this hypothesis through a close examination of some protein structures. A comprehensive set of sequence analysis programs for the Vax.
Acids Res .
Acids Res . Amino acid composition and the evolutionary rates of protein-coding genes. A comprehensive compilation of 1001 nucleotide sequences coding for proteins from the yeast S. cerevisiae . Improved tools for biological sequence comparison. Acids Res .