Impact of H216 on the DNA binding and catalytic activities of the HIV restriction factor APOBEC3G

Stefan Harjes, William C. Solomon, Ming Li, Kuan Ming Chen, Elena Harjes, Reuben S. Harris, Hiroshi Matsuo

Resultado de la investigación: Articlerevisión exhaustiva

45 Citas (Scopus)

Resumen

APOBEC3G has an important role in human defense against retroviral pathogens, including HIV-1. Its single-stranded DNA cytosine deaminase activity, located in its C-terminal domain (A3Gctd), can mutate viral cDNA and restrict infectivity. We used time-resolved nuclear magnetic resonance (NMR) spectroscopy to determine kinetic parameters of A3Gctd's deamination reactions within a 5'-CCC hot spot sequence. A3Gctd exhibited a 45-fold preference for 5'-CCC substrate over 5'-CCU substrate, which explains why A3G displays almost no processivity within a 5'-CCC motif. In addition, A3Gctd's shortest substrate sequence was found to be a pentanucleotide containing 5'-CCC flanked on both sides by a single nucleotide. A3Gctd as well as fulllength A3G showed peak deamination velocities at pH 5.5. We found that H216 is responsible for this pH dependence, suggesting that protonation of H216 could play a key role in substrate binding. Protonation of H216 appeared important for HIV-1 restriction activity as well, since substitutions of H216 resulted in lower restriction in vivo.

Idioma originalEnglish (US)
Páginas (desde-hasta)7008-7014
Número de páginas7
PublicaciónJournal of virology
Volumen87
N.º12
DOI
EstadoPublished - jun. 2013
Publicado de forma externa

ASJC Scopus subject areas

  • Microbiology
  • Immunology
  • Insect Science
  • Virology

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