title: Self-assembled peptides exposing epitopes recognizable by human lymphoma cells.
abstract: A bifunctional N-(2-hydroxypropyl)methacrylamide (HPMA) copolymer containing nitrilotriacetic acid (NTA) and benzophenone (BP) groups was synthesized by free-radical copolymerization of HPMA, 2-methacrylamidobutyl nitrilotriacetic acid (MABNTA), and 4-methacrylamido benzophenone (MABP) using 2, 2'-azobisisobutyronitrile (AIBN) as initiator. A His-tagged coiled coil stem loop peptide containing a tridecapeptide (TDP) epitope (GFLGEDPGFFNVE) in the loop region (CCSL-TDP) was designed and synthesized genetically by expressing an artificial gene in Escherichia coli BL21 (DE3). The peptide was characterized by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), size-exclusion chromatography (SEC), and circular dichroism (CD) spectroscopy. Surfaces containing self-assembled CCSL-TDP peptide were prepared by first covalently grafting poly(HPMA-co-MABNTA-co-MABP) onto polystyrene (PS) surface by UV irradiation, then charging the surface with nickel through NTA groups, and finally attaching the CCSL-TDP peptide through Ni-histidine chelation. The modified PS surfaces with and without self-assembled CCSL-TDP peptide were characterized by X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (TOF-SIMS). Cell attachment studies with human Burkitt's lymphoma Raji B cells showed that the cells selectively bound to the self-assembled CCSL-TDP peptide surfaces, but not to the surfaces of PS, PS with grafted copolymer, and PS with grafted copolymer and self-assembled coiled coil peptide with similar structure but without the epitope. This indicates that the cell attachment was mediated by the CCSL-TDP peptide, most probably by the TDP epitope region. The CCSL peptide self-assembly presented here may represent a feasible model of exposing epitopes for biorecognition studies.
authors.affiliation: Departments of Pharmaceutics and Pharmaceutical Chemistry/CCCD and of Bioengineering, University of Utah, Salt Lake City, Utah 84112, USA.
authors.forename: A
authors.initials: A
authors.lastname: Tang
authors.forename: C
authors.initials: C
authors.lastname: Wang
authors.forename: R
authors.initials: R
authors.lastname: Stewart
authors.forename: J
authors.initials: J
authors.lastname: Kopecek
mesh_terms: D000178:Acrylamides / Q000737:chemistry; D000595:Amino Acid Sequence; D001483:Base Sequence; D001577:Benzophenones / Q000737:chemistry; D002051:Burkitt Lymphoma / Q000188:drug therapy / Q000276:immunology / Q000378:metabolism*; D002462:Cell Membrane / Q000737:chemistry / Q000378:metabolism; D018076:DNA, Complementary / Q000737:chemistry; D004337:Drug Carriers / Q000138:chemical synthesis*; D000939:Epitopes / Q000737:chemistry*; D004926:Escherichia coli / Q000235:genetics; D015870:Gene Expression; D006639:Histidine / Q000737:chemistry; D006801:Humans; D008565:Membrane Proteins / Q000737:chemistry; D008689:Methacrylates / Q000737:chemistry*; D008969:Molecular Sequence Data; D009571:Nitrilotriacetic Acid / Q000031:analogs & derivatives / Q000737:chemistry; D010446:Peptide Fragments / Q000138:chemical synthesis* / Q000737:chemistry / Q000235:genetics; D011108:Polymers / Q000138:chemical synthesis*; D017433:Protein Structure, Secondary; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: C411328:2-methacrylamidobutyl nitrilotriacetic acid; C411327:4-methacylamide benzophenone; D000178:Acrylamides; D001577:Benzophenones; D018076:DNA, Complementary; D004337:Drug Carriers; D000939:Epitopes; D008565:Membrane Proteins; D008689:Methacrylates; D010446:Peptide Fragments; D011108:Polymers; D006639:Histidine; D009571:Nitrilotriacetic Acid; C032802:hydroxypropyl methacrylate