Ja. Xu et al., Evolution of shape complementarity and catalytic efficiency from a primordial antibody template, SCIENCE, 286(5448), 1999, pp. 2345-2348
The crystal structure of an efficient Diels-Alder antibody catalyst at 1.9
angstrom resolution reveals almost perfect shape complementarity with its t
ransition state analog. Comparison with highly related progesterone and Die
ls-Alderase antibodies that arose from the same primordial germ Line templa
te shows the relatively subtle mutational steps that were able to evolve bo
th structural complementarity and catalytic efficiency.