title: Structures of HIV-1 reverse transcriptase with pre- and post-translocation AZTMP-terminated DNA.
abstract: AZT (3'-azido-3'-deoxythymidine) resistance involves the enhanced excision of AZTMP from the end of the primer strand by HIV-1 reverse transcriptase. This reaction can occur when an AZTMP-terminated primer is bound at the nucleotide-binding site (pre-translocation complex N) but not at the 'priming' site (post-translocation complex P). We determined the crystal structures of N and P complexes at 3.0 and 3.1 A resolution. These structures provide insight into the structural basis of AZTMP excision and the mechanism of translocation. Docking of a dNTP in the P complex structure suggests steric crowding in forming a stable ternary complex that should increase the relative amount of the N complex, which is the substrate for excision. Structural differences between complexes N and P suggest that the conserved YMDD loop is involved in translocation, acting as a springboard that helps to propel the primer terminus from the N to the P site after dNMP incorporation.
authors.affiliation: Center for Advanced Biotechnology and Medicine, 679 Hoes Lane, Piscataway, NJ 08854-5638, USA.
authors.forename: Stefan G
authors.initials: SG
authors.lastname: Sarafianos
authors.forename: Arthur D
authors.initials: AD
authors.lastname: Clark
authors.forename: Kalyan
authors.initials: K
authors.lastname: Das
authors.forename: Steve
authors.initials: S
authors.lastname: Tuske
authors.forename: Jens J
authors.initials: JJ
authors.lastname: Birktoft
authors.forename: Palanichamy
authors.initials: P
authors.lastname: Ilankumaran
authors.forename: Andagar R
authors.initials: AR
authors.lastname: Ramesha
authors.forename: Jane M
authors.initials: JM
authors.lastname: Sayer
authors.forename: Donald M
authors.initials: DM
authors.lastname: Jerina
authors.forename: Paul L
authors.initials: PL
authors.lastname: Boyer
authors.forename: Stephen H
authors.initials: SH
authors.lastname: Hughes
authors.forename: Eddy
authors.initials: E
authors.lastname: Arnold
mesh_terms: D004247:DNA / Q000096:biosynthesis / Q000378:metabolism*; D054306:Dideoxynucleotides; D024882:Drug Resistance, Viral / Q000502:physiology; D015497:HIV-1 / Q000378:metabolism*; D006801:Humans; D012194:RNA-Directed DNA Polymerase / Q000378:metabolism*; D013942:Thymine Nucleotides / Q000378:metabolism*; D015215:Zidovudine / Q000031:analogs & derivatives* / Q000378:metabolism*
chemical_list: D054306:Dideoxynucleotides; D013942:Thymine Nucleotides; C057287:3'-azido-3'-deoxythymidine 5'phosphate; D015215:Zidovudine; D004247:DNA; D012194:RNA-Directed DNA Polymerase