Academic Journal
Potential Role for CA-SP in Nucleating Retroviral Capsid Maturation
| العنوان: | Potential Role for CA-SP in Nucleating Retroviral Capsid Maturation |
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| المؤلفون: | England, Matthew R., Purdy, John G., Ropson, Ira J., Dalessio, Paula M., Craven, Rebecca C. |
| المساهمون: | Sundquist, W. I. |
| المصدر: | Journal of Virology ; volume 88, issue 13, page 7170-7177 ; ISSN 0022-538X 1098-5514 |
| بيانات النشر: | American Society for Microbiology |
| سنة النشر: | 2014 |
| الوصف: | During virion maturation, the Rous sarcoma virus (RSV) capsid protein is cleaved from the Gag protein as the proteolytic intermediate CA-SP. Further trimming at two C-terminal sites removes the spacer peptide (SP), producing the mature capsid proteins CA and CA-S. Abundant genetic and structural evidence shows that the SP plays a critical role in stabilizing hexameric Gag interactions that form immature particles. Freeing of CA-SP from Gag breaks immature interfaces and initiates the formation of mature capsids. The transient persistence of CA-SP in maturing virions and the identification of second-site mutations in SP that restore infectivity to maturation-defective mutant viruses led us to hypothesize that SP may play an important role in promoting the assembly of mature capsids. This study presents a biophysical and biochemical characterization of CA-SP and its assembly behavior. Our results confirm cryo-electron microscopy (cryo-EM) structures reported previously by Keller et al. (J. Virol. 87:13655–13664, 2013, doi:10.1128/JVI.01408-13) showing that monomeric CA-SP is fully capable of assembling into capsid-like structures identical to those formed by CA. Furthermore, SP confers aggressive assembly kinetics, which is suggestive of higher-affinity CA-SP interactions than observed with either of the mature capsid proteins. This aggressive assembly is largely independent of the SP amino acid sequence, but the formation of well-ordered particles is sensitive to the presence of the N-terminal β-hairpin. Additionally, CA-SP can nucleate the assembly of CA and CA-S. These results suggest a model in which CA-SP, once separated from the Gag lattice, can actively promote the interactions that form mature capsids and provide a nucleation point for mature capsid assembly. IMPORTANCE The spacer peptide is a documented target for antiretroviral therapy. This study examines the biochemical and biophysical properties of CA-SP, an intermediate form of the retrovirus capsid protein. The results demonstrate a ... |
| نوع الوثيقة: | article in journal/newspaper |
| اللغة: | English |
| DOI: | 10.1128/jvi.00309-14 |
| DOI: | 10.1128/JVI.00309-14 |
| الاتاحة: | http://dx.doi.org/10.1128/jvi.00309-14 https://journals.asm.org/doi/pdf/10.1128/JVI.00309-14 |
| Rights: | https://journals.asm.org/non-commercial-tdm-license |
| رقم الانضمام: | edsbas.CD2E0A93 |
| قاعدة البيانات: | BASE |
| DOI: | 10.1128/jvi.00309-14 |
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