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Basic Characteristics of Mutations
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Mutation Site
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Q577N |
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Mutation Site Sentence
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Q577R only requires a single nucleotide change, while Q577N requires a double mutation and likely occurs stepwise. |
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Mutation Level
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Amino acid level |
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Mutation Type
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Nonsynonymous substitution |
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Gene/Protein/Region
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Env |
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Standardized Encoding Gene
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Env
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Genotype/Subtype
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HIV-1 |
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Viral Reference
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-
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Functional Impact and Mechanisms
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Disease
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HIV Infections
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Immune
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- |
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Target Gene
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-
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Clinical and Epidemiological Correlations
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Clinical Information
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- |
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Treatment
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PIE12-trimer |
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Location
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- |
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Literature Information
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PMID
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31640718
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Title
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Characterization of resistance to a potent D-peptide HIV entry inhibitor
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Author
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Smith AR,Weinstock MT,Siglin AE,Whitby FG,Francis JN,Hill CP,Eckert DM,Root MJ,Kay MS
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Journal
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Retrovirology
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Journal Info
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2019 Oct 22;16(1):28
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Abstract
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BACKGROUND: PIE12-trimer is a highly potent D-peptide HIV-1 entry inhibitor that broadly targets group M isolates. It specifically binds the three identical conserved hydrophobic pockets at the base of the gp41 N-trimer with sub-femtomolar affinity. This extremely high affinity for the transiently exposed gp41 trimer provides a reserve of binding energy (resistance capacitor) to prevent the viral resistance pathway of stepwise accumulation of modest affinity-disrupting mutations. Such modest mutations would not affect PIE12-trimer potency and therefore not confer a selective advantage. Viral passaging in the presence of escalating PIE12-trimer concentrations ultimately selected for PIE12-trimer resistant populations, but required an extremely extended timeframe (> 1 year) in comparison to other entry inhibitors. Eventually, HIV developed resistance to PIE12-trimer by mutating Q577 in the gp41 pocket. RESULTS: Using deep sequence analysis, we identified three mutations at Q577 (R, N and K) in our two PIE12-trimer resistant pools. Each point mutant is capable of conferring the majority of PIE12-trimer resistance seen in the polyclonal pools. Surface plasmon resonance studies demonstrated substantial affinity loss between PIE12-trimer and the Q577R-mutated gp41 pocket. A high-resolution X-ray crystal structure of PIE12 bound to the Q577R pocket revealed the loss of two hydrogen bonds, the repositioning of neighboring residues, and a small decrease in buried surface area. The Q577 mutations in an NL4-3 backbone decreased viral growth rates. Fitness was ultimately rescued in resistant viral pools by a suite of compensatory mutations in gp120 and gp41, of which we identified seven candidates from our sequencing data. CONCLUSIONS: These data show that PIE12-trimer exhibits a high barrier to resistance, as extended passaging was required to develop resistant virus with normal growth rates. The primary resistance mutation, Q577R/N/K, found in the conserved gp41 pocket, substantially decreases inhibitor affinity but also damages viral fitness, and candidate compensatory mutations in gp160 have been identified.
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Sequence Data
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AF324493.2
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