Crossref journal-article
American Society for Microbiology
Journal of Virology (235)
Abstract

ABSTRACT Purified retroviral Gag proteins can assemble in vitro to form immature virus-like particles (VLPs). By cryoelectron tomography, Rous sarcoma virus VLPs show an organized hexameric lattice consisting chiefly of the capsid (CA) domain, with periodic stalk-like densities below the lattice. We hypothesize that the structure represented by these densities is formed by amino acid residues immediately downstream of the folded CA, namely, the short spacer peptide SP, along with a dozen flanking residues. These 24 residues comprise the SP assembly (SPA) domain, and we propose that neighboring SPA units in a Gag hexamer coalesce to form a six-helix bundle. Using in vitro assembly, alanine scanning mutagenesis, and biophysical analyses, we have further characterized the structure and function of SPA. Most of the amino acid residues in SPA could not be mutated individually without abrogating assembly, with the exception of a few residues near the N and C termini, as well as three hydrophilic residues within SPA. We interpret these results to mean that the amino acids that do not tolerate mutations contribute to higher-order structures in VLPs. Hydrogen-deuterium exchange analyses of unassembled Gag compared that of assembled VLPs showed strong protection at the SPA region, consistent with a higher-order structure. Circular dichroism revealed that a 29mer SPA peptide shifts from a random coil to a helix in a concentration-dependent manner. Analytical ultracentrifugation showed concentration-dependent self-association of the peptide into a hexamer. Taken together, these results provide strong evidence for the formation of a critical six-helix bundle in Gag assembly. IMPORTANCE The structure of a retrovirus like HIV is created by several thousand molecules of the viral Gag protein, which assemble to form the known hexagonal protein lattice in the virus particle. How the Gag proteins pack together in the lattice is incompletely understood. A short segment of Gag known to be critical for proper assembly has been hypothesized to form a six-helix bundle, which may be the nucleating event that leads to lattice formation. The experiments reported here, using the avian Rous sarcoma virus as a model system, further define the nature of this segment of Gag, show that it is in a higher-order structure in the virus particle, and provide the first direct evidence that it forms a six-helix bundle in retrovirus assembly. Such knowledge may provide underpinnings for the development of antiretroviral drugs that interfere with virus assembly.

Bibliography

Bush, D. L., Monroe, E. B., Bedwell, G. J., Prevelige, P. E., Phillips, J. M., & Vogt, V. M. (2014). Higher-Order Structure of the Rous Sarcoma Virus SP Assembly Domain. Journal of Virology, 88(10), 5617–5629.

Authors 6
  1. Di L. Bush (first)
  2. Eric B. Monroe (additional)
  3. Gregory J. Bedwell (additional)
  4. Peter E. Prevelige (additional)
  5. Judith M. Phillips (additional)
  6. Volker M. Vogt (additional)
References 90 Referenced 25
  1. 10.1038/nsmb785
  2. 10.1016/j.jmb.2005.10.025
  3. 10.1111/j.1432-1033.1997.t01-1-00592.x
  4. 10.1128/jvi.66.8.4874-4883.1992
  5. 10.1128/JVI.00214-08
  6. 10.1016/S0969-2126(00)00148-9
  7. 10.1038/nature07724
  8. 10.1016/j.str.2009.03.010
  9. 10.1038/35030177
  10. 10.1126/science.283.5398.80
  11. 10.1128/JVI.72.6.4798-4810.1998
  12. 10.1128/JVI.73.3.2270-2279.1999
  13. 10.1016/j.virusres.2010.03.012
  14. 10.1128/JVI.02031-08
  15. 10.1128/JVI.79.23.14498-14506.2005
  16. 10.1128/JVI.75.6.2753-2764.2001
  17. 10.1128/jvi.71.6.4425-4435.1997
  18. 10.1128/jvi.69.10.6487-6497.1995
  19. 10.1128/JVI.72.1.564-577.1998
  20. 10.1128/JVI.74.21.10260-10268.2000
  21. 10.1128/jvi.69.2.1093-1098.1995
  22. 10.1128/JVI.74.18.8452-8459.2000
  23. 10.1128/JVI.02022-09
  24. 10.1128/JVI.05564-11
  25. 10.1128/JVI.05889-11
  26. 10.1128/JVI.76.9.4321-4330.2002
  27. 10.1038/nature11169
  28. 10.1093/emboj/19.1.103
  29. 10.1128/JVI.75.2.759-771.2001
  30. 10.1073/pnas.0903535106
  31. 10.1371/journal.ppat.1001215
  32. 10.1128/JVI.01423-10
  33. 10.1128/JVI.78.5.2545-2552.2004
  34. 10.1016/j.cell.2007.08.018
  35. 10.1038/sj.emboj.7601664
  36. 10.1038/nature09640
  37. 10.1016/j.jmb.2012.01.014
  38. 10.1093/emboj/cdg143
  39. 10.1016/j.jmb.2007.12.043
  40. 10.1016/j.cell.2009.04.063
  41. 10.1016/j.cell.2009.10.010
  42. 10.1371/journal.ppat.1002886
  43. 10.1038/nature12162
  44. 10.1016/S0022-2836(02)01245-7
  45. 10.1038/nsmb790
  46. 10.1016/j.jmb.2003.10.034
  47. 10.1038/emboj.2008.71
  48. 10.1128/jvi.69.6.3407-3419.1995
  49. 10.1128/JVI.72.3.2072-2078.1998
  50. 10.1110/ps.041087605
  51. 10.1128/JVI.00213-08
  52. 10.1128/JVI.00006-11
  53. 10.1128/JVI.77.12.7058-7066.2003
  54. 10.1016/j.jasms.2008.11.019
  55. 10.1016/0003-2697(74)90034-7
  56. 10.1006/abio.1997.2355
  57. 10.1002/psc.987
  58. 10.1128/JVI.78.1.52-60.2004
  59. 10.1016/S0022-2836(02)01176-2
  60. 10.1128/JVI.01926-10
  61. 10.1016/j.str.2010.08.016
  62. 10.1126/science.278.5339.849
  63. 10.1038/nsb0996-763
  64. 10.1017/S003358359800345X
  65. 10.1006/jmbi.1994.0015
  66. 10.1002/pro.5560021206
  67. 10.1006/jmbi.1995.0651
  68. 10.1016/S1359-0278(96)00039-9
  69. SchachmanHK. 1959. Ultracentrifugation in biochemistry. Academic Press, New York, NY. / Ultracentrifugation in biochemistry by Schachman HK (1959)
  70. 10.1128/JVI.74.16.7578-7586.2000
  71. 10.1016/j.jmb.2007.02.079
  72. 10.1038/nchembio.692
  73. 10.1016/j.jmb.2009.04.006
  74. 10.1006/jmbi.1999.3475
  75. 10.1093/emboj/17.6.1555
  76. 10.1016/j.jmb.2009.01.058
  77. 10.1128/JVI.74.1.16-23.2000
  78. 10.1128/jvi.66.12.7005-7011.1992
  79. 10.1016/j.virol.2007.03.053
  80. 10.1128/JVI.76.21.10811-10820.2002
  81. 10.1128/JVI.74.16.7250-7260.2000
  82. 10.1128/JVI.79.7.4159-4169.2005
  83. 10.1128/jvi.67.10.6246-6252.1993
  84. 10.1128/JVI.76.22.11729-11737.2002
  85. 10.1128/JVI.78.2.551-560.2004
  86. 10.1128/JVI.74.16.7238-7249.2000
  87. 10.1128/jvi.68.12.8017-8027.1994
  88. 10.1128/jvi.69.10.6430-6438.1995
  89. 10.1371/journal.ppat.1002997
  90. 10.1128/JVI.75.15.6850-6856.2001
Dates
Type When
Created 11 years, 5 months ago (March 5, 2014, 11:16 p.m.)
Deposited 3 years, 5 months ago (March 5, 2022, 10:37 a.m.)
Indexed 1 year ago (Aug. 3, 2024, 4:59 p.m.)
Issued 11 years, 3 months ago (May 15, 2014)
Published 11 years, 3 months ago (May 15, 2014)
Published Print 11 years, 3 months ago (May 15, 2014)
Funders 0

None

@article{Bush_2014, title={Higher-Order Structure of the Rous Sarcoma Virus SP Assembly Domain}, volume={88}, ISSN={1098-5514}, url={http://dx.doi.org/10.1128/jvi.02659-13}, DOI={10.1128/jvi.02659-13}, number={10}, journal={Journal of Virology}, publisher={American Society for Microbiology}, author={Bush, Di L. and Monroe, Eric B. and Bedwell, Gregory J. and Prevelige, Peter E. and Phillips, Judith M. and Vogt, Volker M.}, editor={Sundquist, W. I.}, year={2014}, month=may, pages={5617–5629} }