Display Settings:

Items per page

Results: 7

1.
FIG. 2.

FIG. 2. From: Heptad Repeat 2-Based Peptides Inhibit Avian Sarcoma and Leukosis Virus Subgroup A Infection and Identify a Fusion Intermediate.

Peptide inhibition of infection. (A) MLV(EnvA) pseudotypes were used to infect QT6 cells in the presence of R99 (squares), R102 (circles), or Ebola virus-derived E112 (triangles). (B) ASLV-A [RCAS(A)AP] was used to infect TEF cells in the presence of R99 (squares) or R102 (circles). Percent infectivity is relative to the titer in the absence of peptide. Each data point is the average of three experiments, and error bars indicate standard deviations.

Robert C. Netter, et al. J Virol. 2004 December;78(24):13430-13439.
2.
FIG. 3.

FIG. 3. From: Heptad Repeat 2-Based Peptides Inhibit Avian Sarcoma and Leukosis Virus Subgroup A Infection and Identify a Fusion Intermediate.

Effect of single amino acid substitutions in HR1 on sensitivity to HR2 peptides. MLV(EnvA) pseudotypes were generated with either wild-type ASLV-A envelope (diamonds) or HR1 mutants T55A (triangles), L62A (squares), or R69E (circles). Virus was incubated with either R102 (A) or R99 (B) for 2 min at room temperature prior to challenging QT6 cells. Percent infectivity is relative to the titer in the absence of peptide. Data points are the averages of three experiments (wild type and L62A) with error bars marking standard deviations, or they are from a single representative experiment (T55A and R69E).

Robert C. Netter, et al. J Virol. 2004 December;78(24):13430-13439.
3.
FIG. 5.

FIG. 5. From: Heptad Repeat 2-Based Peptides Inhibit Avian Sarcoma and Leukosis Virus Subgroup A Infection and Identify a Fusion Intermediate.

Inhibition of cell-cell fusion by HR2 peptide occurs prior to acid activation. Transfected 293T cells expressing ASLV-A envelope and HIV-1 Tat were seeded in an equimolar ratio with HeLa-MAGI cells stably expressing the Tva receptor. Cells were allowed to attach for 3 h, washed, pulsed with low-pH medium (pH 5.25), washed again, and assayed for β-galactosidase activity 12 h later. R99 was included at 5 μg/ml during the 3-h attachment period (lane 3), during the acid pulse (lane 4), during the 12-h recovery phase (lane 5), or throughout the entire assay (lane 2). Lane 1 is a control in which R99 was not used.

Robert C. Netter, et al. J Virol. 2004 December;78(24):13430-13439.
4.
FIG. 6.

FIG. 6. From: Heptad Repeat 2-Based Peptides Inhibit Avian Sarcoma and Leukosis Virus Subgroup A Infection and Identify a Fusion Intermediate.

Liposome binding is not blocked by HR2 peptides. Sucrose step gradients were used to separate liposomes by their buoyant densities. Soluble, oligomeric ASLV-A envelope (A) or ASLV-A virions (B) were incubated with or without soluble receptor (sTva) to activate envelope in the presence or absence of HR2 peptides. The R102 peptide was used at a concentration of 50 μg/ml (A), and R99 was used at 30 μg/ml (B). Each fraction (top, middle, bottom) was examined by SDS-PAGE and Western blotting with antisera against either the SU (A) or TM (B) subunit. Samples were loaded in the dense bottom fraction, so that liposome-associated material would float to the upper, less-dense fractions. The retarded migration of SU in the bottom fraction of the first gradient in panel A is an SDS-PAGE artifact.

Robert C. Netter, et al. J Virol. 2004 December;78(24):13430-13439.
5.
FIG. 7.

FIG. 7. From: Heptad Repeat 2-Based Peptides Inhibit Avian Sarcoma and Leukosis Virus Subgroup A Infection and Identify a Fusion Intermediate.

HR2 peptide binds to a triggered form of TM. ASLV-A was incubated on ice with combinations of soluble receptor (sTva), liposomes, and/or the HR2 peptide R99, triggered at 37°C, and then cross-linked on ice. Samples were examined by SDS-PAGE and Western blotting and probed with horseradish peroxidase-conjugated streptavidin to detect biotinylated R99 (R99-Bio). Locations of molecular mass standards are shown on the left of each blot. (A) R99-Bio is detected in a position consistent with binding to triggered, oligomeric TM and can be competed by unlabeled R99. The band labeled TM90 migrates somewhat slower than triggered TM in the absence of HR2 peptide (see Results). Soluble receptor (sTva) and/or liposomes were added to the reaction mixture as indicated. Unlabeled R99 was included either in an equimolar amount (1×) or as a 10-fold excess (10×) to R99-Bio, as shown. (B) Appearance of R99-Bio in the TM90 position is dependent upon incubation time at 37°C. (C) TM90 is efficiently immunoprecipitated by antiserum directed against the TM subunit.

Robert C. Netter, et al. J Virol. 2004 December;78(24):13430-13439.
6.
FIG. 1.

FIG. 1. From: Heptad Repeat 2-Based Peptides Inhibit Avian Sarcoma and Leukosis Virus Subgroup A Infection and Identify a Fusion Intermediate.

Comparison of the TM subunit of ASLV-A envelope with Ebola virus GP2. (A) Schematic diagram of the ASLV-A envelope. The fill patterns depict the predicted domains of the TM subunit as follows: diagonal lines, fusion peptide (FP); shaded, N- and C-terminal HRs (HR1 and HR2); horizontal lines, membrane-spanning domain (MSD). Shown below the schematic diagram is a sequence alignment of the heptad repeats and intervening sequences from the TM of ASLV-A and Ebola virus GP2 (Zaire subtype), with the one-letter amino acid code. For the Ebola sequence, dots indicate amino acids identical to ASLV-A TM and the asterisk in the ASLV-A sequence designates a space introduced in order to align the two sequences (, ). The cylinders mark regions predicted to be helical, and the brackets indicate the sequence of synthetic peptides. (B) Ribbon diagram showing the structure of Ebola virus GP2 () using RasMol modeling. The substitutions introduced into the HR1 domain of the TM subunit of ASLV-A are each in positions for which the sequence alignment displays identical residues between the two viruses; the side chains for these mutated residues are shown (ASLV numbering). The region corresponding to E109 and R99 is shown in dark.

Robert C. Netter, et al. J Virol. 2004 December;78(24):13430-13439.
7.
FIG. 4.

FIG. 4. From: Heptad Repeat 2-Based Peptides Inhibit Avian Sarcoma and Leukosis Virus Subgroup A Infection and Identify a Fusion Intermediate.

Sensitivity to HR2 peptide as a function of time at 37°C. Pseudotyped virus was allowed to bind QT6 cells at 4°C, and then unbound virus was washed away. (A) Peptide removal experiment to determine the time at which the R99 binding site is exposed. Cold medium containing 10 μg of R99/ml and 80 nM sTva was added to cells, and 1 h later cells were rapidly warmed to 37°C. For each time point, cells were washed to remove peptide and then returned to 37°C. Infectivity is normalized to a control in which the peptide was washed away prior to the warm-up step. Data points are averages of three replicates. (B) Peptide addition experiment to assess the longevity of its efficacy. Cells were warmed to 37°C, and R99 was added to a final concentration of 10 (wild-type) or 50 (L62A) μg/ml at the indicated time. MLV pseudotypes bore either a wild-type ASLV-A envelope (squares) or the L62A mutant (circles). For each pseudotype, infectivity was normalized to a control in which peptide was not added. Each data point is the average of three replicates.

Robert C. Netter, et al. J Virol. 2004 December;78(24):13430-13439.

Display Settings:

Items per page

Supplemental Content

Recent activity

Your browsing activity is empty.

Activity recording is turned off.

Turn recording back on

See more...
Write to the Help Desk