1.D.17  The Combinatorially-designed, Pore-forming, β-sheet Peptide (CPβ-Peptide) Family
 
Exogenous polypeptides that self-assemble on biological membranes into pores are abundant and structurally diverse, functioning as transporters, toxins, ion channels, and antibiotics. A rational combinatorial peptide library was designed, based on the structural principles of known membrane-spanning beta-sheets. When the library was screened under stringent conditions for sequences with pore-forming activity, a single active motif was found, which is characterized by aromatic residues at the lipid-exposed interfacial positions and basic residues in the pore-lining portion of the sequence. Peptides with this motif assembled on bilayer membranes into beta-sheets and formed transient peptide/lipid pores of approximately 1-nm diameter. The mechanism of action is very similar to that of natural, pore-forming peptides (Rausch et al., 2005; 2007).
 
Sequences of the most potent pore-forming peptides selected form the combinatorial library are presented below. Residues in bold/underline are positions that were varied in the library.
 
Pore-forming β-strand:
FSSSTL: RRGFSLSLALAKDGWALMLSLTLGRR
FSGRGY{dagger}: RRGFSLGLALAKDGWALMLRLGYGRR
FSKGGY: RRGFSLKLALAKDGWALMLGLGYGRR
YGTKTF: RRGYGLTLALAKDGWALMLKLTFGRR
YGKRGY: RRGYGLKLALAKDGWALMLRLGYGRR
FSSRGY{dagger}: RRGFSLSLALAKDGWALMLRLGYGRR
YSRRTF: RRGYSLRLALAKDGWALMLRLTFGRR
FSRKTY: RRGFSLRLALAKDGWALMLKLTYGRR
LSRRGF: RRGLSLRLALAKDGWALMLRLGFGRR
YGKRGF{dagger}: RRGYGLKLALAKDGWALMLRLGFGRR
FSKRGF: RRGFSLKLALAKDGWALMLRLGFGRR
FGRRTF: RRGFGLRLALAKDGWALMLRLTFGRR
{dagger} These sequences were synthesized and purified for detailed characterization of pore-forming activity.


 

References:

Rausch, J.M., J.R. Marks, and W.C. Wimley. (2005). Rational combinatorial design of pore-forming beta-sheet peptides. Proc. Natl. Acad. Sci. U.S.A. 102(30):10511-10515.
Rausch, J.M., J.R. Marks, R. Rathinakumar, and W.C. Wimley. (2007). Beta-sheet pore-forming peptides selected from a rational combinatorial library: mechanism of pore formation in lipid vesicles and activity in biological membranes. Biochemistry. 46(43):12124-12139.