Evolution
All aspartate proteases have a highly conserved sequence of Asp-Thr-Gly. In general, with the exception of HIV - a dimer of two identical subunits - these enzymes are monomeric enzymes consisting of two domains. Because of this organisation, it is thought that these domains may have arisen through ancestral gene duplication.
Read more about this topic: Aspartic Acid Proteases
Famous quotes containing the word evolution:
“By contrast with history, evolution is an unconscious process. Another, and perhaps a better way of putting it would be to say that evolution is a natural process, history a human one.... Insofar as we treat man as a part of nature—for instance in a biological survey of evolution—we are precisely not treating him as a historical being. As a historically developing being, he is set over against nature, both as a knower and as a doer.”
—Owen Barfield (b. 1898)
“Analyze theory-building how we will, we all must start in the middle. Our conceptual firsts are middle-sized, middle-distanced objects, and our introduction to them and to everything comes midway in the cultural evolution of the race.”
—Willard Van Orman Quine (b. 1908)
“Historians will have to face the fact that natural selection determined the evolution of cultures in the same manner as it did that of species.”
—Konrad Lorenz (1903–1989)