On the Emergence of New Function in PrimitiveiBrote (original) (raw)

The problem of creating proteins with new functions out of already existing proteins is treated in some detail. It is shown that the generally accepted process of a gene-duplication followed by random mutational events should have been inefficient as a means of evolution in primitive cells. An alternative scheme, based on considerations of protein folding processes, is presented, and is shown, by the means of a specific example, to give a consistent picture of the evolution of primitive proteins with new functions.

Evolution before and after gene duplication?

Most hypotheses about the evolution of new proteins via the mecha- nism of gene duplication and divergence only take into account the pro- cesses following the duplication event. The Neofunctionalisation hypothe- sis assumes that, due to the functional redundancy of the two gene copies, one is free to undergo adaptation towards a new function. The Subfunc- tionalisation hypothesis, assumes that, for a while, the duplicates retain complementary subfunctions of the original gene. Here, we review evi- dence for adaptive changes occurring in proteins (or single protein do- mains) that have not (yet) undergone gene duplication. These changes are neutral with respect to the fitness contribution of the native function of a protein, but potentially adaptive regarding the fitness contributions of latent or promiscuous functions. It is likely that those promiscuous functions are associated with different protein conformations existing in equilibrium. If a gene duplication occurs for a protein...

The Adaptation of Complexity in the Evolution of Macromolecules

2009

Enzymes are on the front lines of evolution. All living organisms rely on highly efficient, specific enzymes for growth, sustenance, and reproduction; and many diseases are a consequence of a mutation on an enzyme that affects its catalytic function. It follows that the function of an enzyme affects the fitness of an organism, but just as rightfully true, the function of an enzyme affects the fitness of itself. Understanding how the complexity of enzyme structure relates to its essential function will unveil the fundamental mechanisms of evolution, and, perhaps, shed light on strategies used by ancient replicators. This paper presents evidence that supports the hypothesis that enzymes, and proteins in general, are the manifestation of the coevolution of two opposing forces. The synthesis of enzyme architecture, stability, function, evolutionary relationships, and evolvability shows that the complexity of macromolecules is a consequence of the function it provides.

Protein evolution

2011

On the origin of proteins A series of mistakes over the past 3.7 billion years or so has left us with a spectacular array of protein structures and functions, which are responsible for nothing less than life itself, writes Bea Perks

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