Bottom - Index of papers - Previous - Next - Paper in HTML - Abstract - CUBIC
| Title: | Protein structures sustain evolutionary drift |
| Author: | Burkhard Rost |
| Quote: | Folding & Design, 2, 519-524 (1997) |
A protein sequence folds into a unique three-dimensional protein structure. Different sequences, though, can fold into similar structures. How stable is a protein structure with respect to sequence changes? What percentage of the sequence are 'anchor' residues, i.e., are crucial for protein structure and function? Here, these questions are pursued by analysing large numbers of structurally homologous protein pairs. Most pairs of similar structures have sequence identity as low as expected from randomly related sequences. On average only three to four percent of all residues are 'anchor' residues (residues crucial for maintaining the structure). The symmetric shape of the distribution at low sequence identity suggests that for most structures, four billion years of evolution was sufficient to reach an equilibrium. The mean identities for convergent (different ancestor) and divergent evolution (same ancestor) of proteins to similar structures are quite close, and hence, in most cases it is difficult to distinguish between the two effects. In particular, low levels of sequence identity appear not to be indicative of convergent evolution.
Top -
Index of papers -
Previous -
Next -
Paper in HTML -
Abstract -
CUBIC