APOBEC3G subunits self-associate via the C-terminal deaminase domain.
Human APOBEC3G (hA3G) is a cytidine deaminase active on HIV single-stranded DNA. Small angle x-ray scattering and molecular envelope restorations predicted a C-terminal dimeric model for RNA-depleted hA3G in solution. Each subunit was elongated, suggesting that individual domains of hA3G are solvent-exposed and therefore may interact with other macromolecules even as isolated substructures. In this study, co-immunoprecipitation and in-cell quenched fluorescence resonance energy transfer assays reveal that hA3G forms RNA-independent oligomers through interactions within its C terminus. Residues 209-336 were necessary and sufficient for homoligomerization. N-terminal domains of hA3G were unable to multimerize but remained functional for Gag and viral infectivity factor (Vif) interactions when expressed apart from the C terminus. These findings corroborate the small angle x-ray scattering structural model and are instructive for development of high throughput screens that target specific domains and their functions to identify HIV/AIDS therapeutics.
Department of Biochemistry and Biophysics, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642, USA.
Ryan P
RP
Bennett
Jason D
JD
Salter
Xiang
X
Liu
Joseph E
JE
Wedekind
Harold C
HC
Smith
D000071480:APOBEC-3G Deaminase; D002460:Cell Line; D003564:Cytidine Deaminase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D004277:DNA, Single-Stranded / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D004279:DNA, Viral / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D019281:Dimerization; D016655:HIV Core Protein p24 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015497:HIV-1 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D008958:Models, Molecular; D020836:Protein Structure, Quaternary; D017434:Protein Structure, Tertiary / Q000502:physiology; D054320:vif Gene Products, Human Immunodeficiency Virus / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
D004277:DNA, Single-Stranded; D004279:DNA, Viral; D016655:HIV Core Protein p24; C514799:p24 protein, Human Immunodeficiency Virus Type 1; D054320:vif Gene Products, Human Immunodeficiency Virus; C514847:vif protein, Human immunodeficiency virus 1; D000071480:APOBEC-3G Deaminase; C464924:APOBEC3G protein, human; D003564:Cytidine Deaminase