title: Peptide specificity and lipid activation of the lysosomal transport complex ABCB9 (TAPL).
abstract: The lysosomal ABC transporter associated with antigen processing-like (TAPL, ABCB9) acts as an ATP-dependent polypeptide transporter with broad length selectivity. To characterize in detail its substrate specificity, a procedure for functional reconstitution of human TAPL was developed. By intensive screening of detergents, ideal solubilization conditions were evolved with respect to efficiency, long term stability, and functionality of TAPL. TAPL was isolated in a two-step procedure with high purity and, subsequently, reconstituted into proteoliposomes. The peptide transport activity of reconstituted TAPL strongly depends on the lipid composition. With the help of combinatorial peptide libraries, the key positions of the peptides were localized to the N- and C-terminal residues with respect to peptide transport. At both ends, TAPL favors positively charged, aromatic, or hydrophobic residues and disfavors negatively charged residues as well as asparagine and methionine. Besides specific interactions of both terminal residues, electrostatic interactions are important, since peptides with positive net charge are more efficiently transported than negatively charged ones.
authors.affiliation: Institute of Biochemistry, Biocenter, Goethe-University Frankfurt, Max-von-Laue-Strasse 9, D-60438 Frankfurt am Main, Germany.
authors.forename: Chenguang
authors.initials: C
authors.lastname: Zhao
authors.forename: Winfried
authors.initials: W
authors.lastname: Haase
authors.forename: Robert
authors.initials: R
authors.lastname: Tampé
authors.forename: Rupert
authors.initials: R
authors.lastname: Abele
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000737:chemistry*; D000941:Antigens / Q000737:chemistry; D001216:Asparagine / Q000737:chemistry; D001671:Biochemistry / Q000379:methods; D001692:Biological Transport; D003902:Detergents / Q000737:chemistry / Q000494:pharmacology; D006801:Humans; D008055:Lipids / Q000737:chemistry; D008715:Methionine / Q000737:chemistry; D019151:Peptide Library; D010455:Peptides / Q000737:chemistry*; D017434:Protein Structure, Tertiary; D055672:Static Electricity; D013379:Substrate Specificity; D014018:Tissue Distribution
chemical_list: C412573:ABCB9 protein, human; D018528:ATP-Binding Cassette Transporters; D000941:Antigens; D003902:Detergents; D008055:Lipids; D019151:Peptide Library; D010455:Peptides; D001216:Asparagine; D008715:Methionine