Never Born Proteins and Never Born Peptidases: Investigation of Peptidase Activity in a Totally Random Library

摘要

The “Never Born Proteins” (NBP) project is based on the concept that the fraction of proteins existing in nature is a minimal part of all theoretical amino acid sequences. An important question is how this fraction of proteins was selected during pre-biotic era. These proteins could have been selected by evolution because they have some particular thermodynamics properties (e.g., thermodynamic or kinetic stability, solubility, etc.); this idea is close to the deterministic point of view supported by de Duve (De Duve, 1995). According to this idea, it is possible to think that the protein existing in nature are the result of the selective pressure, but also the optimal solution to biological necessity. Alternatively, these proteins could be simply the products of contingency, i.e., concomitant accidental environmental conditions that have determined proteins’ evolution, in accordance with the theories of other scientists like Monod (Monod, 1971).