PT  - JOURNAL ARTICLE
AU  - Ivo R. Ruttekolk
AU  - Alokta Chakrabarti
AU  - Martin Richter
AU  - Falk Duchardt
AU  - Heike Glauner
AU  - Wouter P. R. Verdurmen
AU  - Jörg Rademann
AU  - Roland Brock
TI  - Coupling to Polymeric Scaffolds Stabilizes Biofunctional Peptides for Intracellular Applications
AID  - 10.1124/mol.110.068296
DP  - 2011 Apr 01
TA  - Molecular Pharmacology
PG  - 692--700
VI  - 79
IP  - 4
4099  - http://molpharm.aspetjournals.org/content/79/4/692.short
4100  - http://molpharm.aspetjournals.org/content/79/4/692.full
SO  - Mol Pharmacol2011 Apr 01; 79
AB  - Here, we demonstrate that coupling to N-hydroxypropyl methacrylamide (HPMA) copolymer greatly enhances the activity of apoptosis-inducing peptides inside cells. Peptides corresponding to the BH3 domain of Bid were coupled to a thioester-activated HPMA (28.5 kDa) via native chemical ligation in a simple one-pot synthesis. Peptides and polymer conjugates were introduced into cells either by electroporation or by conjugation to the cell-penetrating peptide nona-arginine. The molecular basis of the increased activity is elucidated in detail. Loading efficiency and intracellular residence time were assessed by confocal microscopy. Fluorescence correlation spectroscopy was used as a separation-free analytical technique to determine proteolytic degradation in crude cell lysates. HPMA conjugation strongly increased the half-life of the peptides in crude cell lysates and inside cells, revealing proteolytic protection as the basis for higher activity.