title: The design, synthesis, and evaluation of molecules that enable or enhance cellular uptake: peptoid molecular transporters.
abstract: Certain proteins contain subunits that enable their active translocation across the plasma membrane into cells. In the specific case of HIV-1, this subunit is the basic domain Tat(49-57) (RKKRRQRRR). To establish the optimal structural requirements for this translocation process, and thereby to develop improved molecular transporters that could deliver agents into cells, a series of analogues of Tat(49-57) were prepared and their cellular uptake into Jurkat cells was determined by flow cytometry. All truncated and alanine-substituted analogues exhibited diminished cellular uptake, suggesting that the cationic residues of Tat(49-57) play a principal role in its uptake. Charge alone, however, is insufficient for transport as oligomers of several cationic amino acids (histidine, lysine, and ornithine) are less effective than Tat(49-57) in cellular uptake. In contrast, a 9-mer of l-arginine (R9) was 20-fold more efficient than Tat(49-57) at cellular uptake as determined by Michaelis-Menton kinetic analysis. The d-arginine oligomer (r9) exhibited an even greater uptake rate enhancement (>100-fold). Collectively, these studies suggest that the guanidinium groups of Tat(49-57) play a greater role in facilitating cellular uptake than either charge or backbone structure. Based on this analysis, we designed and synthesized a class of polyguanidine peptoid derivatives. Remarkably, the subset of peptoid analogues containing a six-methylene spacer between the guanidine head group and backbone (N-hxg), exhibited significantly enhanced cellular uptake compared to Tat(49-57) and even to r9. Overall, a transporter has been developed that is superior to Tat(49-57), protease resistant, and more readily and economically prepared.
authors.affiliation: Departments of Chemistry and Neurology, Stanford University, Stanford, CA 94305-5080, USA. wenderp@leland.stanford.edu
authors.forename: P A
authors.initials: PA
authors.lastname: Wender
authors.forename: D J
authors.initials: DJ
authors.lastname: Mitchell
authors.forename: K
authors.initials: K
authors.lastname: Pattabiraman
authors.forename: E T
authors.initials: ET
authors.lastname: Pelkey
authors.forename: L
authors.initials: L
authors.lastname: Steinman
authors.forename: J B
authors.initials: JB
authors.lastname: Rothbard
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001402:B-Lymphocytes / Q000378:metabolism; D001692:Biological Transport; D002352:Carrier Proteins / Q000138:chemical synthesis / Q000737:chemistry* / Q000378:metabolism; D002478:Cells, Cultured; D015195:Drug Design; D015696:Gene Products, tat / Q000737:chemistry* / Q000378:metabolism; D015497:HIV-1 / Q000378:metabolism; D006801:Humans; D019169:Jurkat Cells; D007700:Kinetics; D008214:Lymphocytes / Q000378:metabolism; D051379:Mice; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry; D010455:Peptides / Q000138:chemical synthesis / Q000737:chemistry* / Q000493:pharmacokinetics*; D034444:Peptoids; D021122:Protein Subunits; D054322:tat Gene Products, Human Immunodeficiency Virus
chemical_list: D002352:Carrier Proteins; D015696:Gene Products, tat; D010446:Peptide Fragments; D010455:Peptides; D034444:Peptoids; D021122:Protein Subunits; D054322:tat Gene Products, Human Immunodeficiency Virus