title: Mechanisms of HIV-1 Nucleocapsid Protein Inhibition by Lysyl-Peptidyl-Anthraquinone Conjugates.
abstract: The Nucleocapsid protein NCp7 (NC) is a nucleic acid chaperone responsible for essential steps of the HIV-1 life cycle and an attractive candidate for drug development. NC destabilizes nucleic acid structures and promotes the formation of annealed substrates for HIV-1 reverse transcription elongation. Short helical nucleic acid segments bordered by bulges and loops, such as the Trans-Activation Response element (TAR) of HIV-1 and its complementary sequence (cTAR), are nucleation elements for helix destabilization by NC and also preferred recognition sites for threading intercalators. Inspired by these observations, we have recently demonstrated that 2,6-disubstituted peptidyl-anthraquinone-conjugates inhibit the chaperone activities of recombinant NC in vitro, and that inhibition correlates with the stabilization of TAR and cTAR stem-loop structures. We describe here enhanced NC inhibitory activity by novel conjugates that exhibit longer peptidyl chains ending with a conserved N-terminal lysine. Their efficient inhibition of TAR/cTAR annealing mediated by NC originates from the combination of at least three different mechanisms, namely, their stabilizing effects on nucleic acids dynamics by threading intercalation, their ability to target TAR RNA substrate leading to a direct competition with the protein for the same binding sites on TAR, and, finally, their effective binding to the NC protein. Our results suggest that these molecules may represent the stepping-stone for the future development of NC-inhibitors capable of targeting the protein itself and its recognition site in RNA.
authors.forename: Alice
authors.initials: A
authors.lastname: Sosic
authors.forename: Laura
authors.initials: L
authors.lastname: Sinigaglia
authors.forename: Marta
authors.initials: M
authors.lastname: Cappellini
authors.forename: Ilaria
authors.initials: I
authors.lastname: Carli
authors.forename: Cristina
authors.initials: C
authors.lastname: Parolin
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Zagotto
authors.affiliation: Espikem SRL , Sesto Fiorentino, 50019 Firenze, Italy.
authors.forename: Giuseppina
authors.initials: G
authors.lastname: Sabatino
authors.affiliation: Dipartimento NeuroFarBa, Sezione di Scienze Farmaceutiche e Nutraceutica, Università di Firenze , 50121 Firenze, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Rovero
authors.affiliation: Department of Chemistry, State University of New York , Albany, New York 12222, United States.
authors.forename: Dan
authors.initials: D
authors.lastname: Fabris
authors.forename: Barbara
authors.initials: B
authors.lastname: Gatto
mesh_terms: D000880:Anthraquinones / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D001665:Binding Sites; D016325:HIV Long Terminal Repeat; D008239:Lysine / Q000737:chemistry; D009696:Nucleic Acids / Q000737:chemistry; D012367:RNA, Viral / Q000378:metabolism; D054301:gag Gene Products, Human Immunodeficiency Virus / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000378:metabolism*
chemical_list: D000880:Anthraquinones; C071884:NCP7 protein, Human immunodeficiency virus 1; D009696:Nucleic Acids; D012367:RNA, Viral; D054301:gag Gene Products, Human Immunodeficiency Virus; D008239:Lysine