Chemical activity of simple basic peptides.
Alternating all-L poly(leucyl-lysyl) increases markedly the rate of hydrolysis of oligoribonucleotides. Pure D poly (leucyl-lysyl) is as active as the all-L polymer. The homochiral polypeptides adopt a beta-sheet structure when complexed to the oligonucleotides. Alternating poly(D,L-Leu-D,L-Lys) made of racemic amino acids is much less efficient and is unable to adopt a beta-sheet structure. A set of alternating poly (leucyl-lysyl) ranging from the racemic to the homochiral all-L polymer has been checked. Their conformations can be described as a mixture of random coil and beta-sheet conformations, the amount of beta-sheet increasing with the optical purity of the polymer. The hydrolytic activity follows the proportion of beta-sheets, suggesting that the chemical activity is related to the geometry of the chain. Short peptides were prepared in order to evaluate the critical chain length required for the hydrolytic activity. A decapeptide is long enough to present 90% of the activity of the corresponding polypeptide.
Brack
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A
Centre de Biophysique Moléculaire, C.N.R.S., Orléans, France.
Barbier
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B
D000595:Amino Acid Sequence; D006868:Hydrolysis; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry*; D011108:Polymers; D011487:Protein Conformation
D010455:Peptides; D011108:Polymers