The preparation of synthetic molecules showing the remarkable efficien
cies characteristic of natural biopolymer catalysts remains a formidab
le challenge for chemical biology, Although significant advances have
been made in the understanding of protein structure and function, the
ne novo construction of such systems remains elusive(1-5). Re-engineer
ed natural enzymes and catalytic antibodies, possessing tailored bindi
ng pockets with appropriately positioned functional groups, have been
successful in catalysing a number of chemical transformations, sometim
es with impressive efficiencies(6-11). But efforts to produce wholly s
ynthetic catalytic peptides have typically resulted in compounds with
questionable structural stability, let alone reactivity(1). Here we de
scribe a 33-residue synthetic peptide, based on the coiled-coil struct
ural motif(12-14), which efficiently catalyses the condensation of two
shorter peptide fragments with high sequence-and diastereoselectivity
. Depending on the substrates used, we observe rate enhancements of te
nfold to 4,100-fold over the background, with catalytic efficiencies i
n excess of 10(4). These results augur well for the rational design of
functional peptides.