| תקציר: | Proteins are the machinery of life, and enzymes are especially critical in directing and accelerating the rate of all biochemical processes. The earliest living form which is tractable, the so-called Last Universal Common Ancestor, LUCA, was already equipped with a large set of fully functional enzymes. As far as phylogenetic analysis can reveal, these LUCA enzymes were essentially identical to their modern descents – namely large and complex proteins. How these evolved from shorter and simpler proteins (or peptides) remains enigmatic. I will describe our efforts to infer the early pre-LUCA precursors, reconstruct and test them in the laboratory, and also what these precursors teach us about the earliest stages of protein evolution. |