TY - JOUR
T1 - Mechanism of Action of Peptides That Cause the pH-Triggered Macromolecular Poration of Lipid Bilayers
AU - Kim, Sarah Y.
AU - Pittman, Anna E.
AU - Zapata-Mercado, Elmer
AU - King, Gavin M.
AU - Wimley, William C.
AU - Hristova, Kalina
N1 - Funding Information:
Funded by NSF DMR 1709892 (K.H.), NSF DMR 1709792 (G.M.K.) and NIH R01 GM111824 and NSF DMR 1710053 (W.C.W.).
Publisher Copyright:
© 2019 American Chemical Society.
PY - 2019/4/24
Y1 - 2019/4/24
N2 - Using synthetic molecular evolution, we previously discovered a family of peptides that cause macromolecular poration in synthetic membranes at low peptide concentration in a way that is triggered by acidic pH. To understand the mechanism of action of these "pHD peptides", here we systematically explored structure-function relationships through measurements of the effect of pH and peptide concentration on membrane binding, peptide structure, and the formation of macromolecular-sized pores in membranes. Both AFM and functional assays demonstrate the peptide-induced appearance of large pores in bilayers. Pore formation has a very steep pH dependence and is also dependent on peptide concentration. In vesicles, 50% leakage of 40 kDa dextrans occurs at 1 bound peptide per 1300 lipids or only 75 peptides per vesicle, an observation that holds true across a wide range of acidic pH values. The major role of pH is to regulate the amount of peptide bound per vesicle. The physical chemistry and sequence of the pHD peptides affect their potency and pH dependence; therefore, the sequence-structure-function relationships described here can be used for the future design and optimization of membrane permeabilizing peptides for specific applications.
AB - Using synthetic molecular evolution, we previously discovered a family of peptides that cause macromolecular poration in synthetic membranes at low peptide concentration in a way that is triggered by acidic pH. To understand the mechanism of action of these "pHD peptides", here we systematically explored structure-function relationships through measurements of the effect of pH and peptide concentration on membrane binding, peptide structure, and the formation of macromolecular-sized pores in membranes. Both AFM and functional assays demonstrate the peptide-induced appearance of large pores in bilayers. Pore formation has a very steep pH dependence and is also dependent on peptide concentration. In vesicles, 50% leakage of 40 kDa dextrans occurs at 1 bound peptide per 1300 lipids or only 75 peptides per vesicle, an observation that holds true across a wide range of acidic pH values. The major role of pH is to regulate the amount of peptide bound per vesicle. The physical chemistry and sequence of the pHD peptides affect their potency and pH dependence; therefore, the sequence-structure-function relationships described here can be used for the future design and optimization of membrane permeabilizing peptides for specific applications.
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U2 - 10.1021/jacs.9b01970
DO - 10.1021/jacs.9b01970
M3 - Article
C2 - 30916949
AN - SCOPUS:85064982355
SN - 0002-7863
VL - 141
SP - 6706
EP - 6718
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
IS - 16
ER -