6p59 | pdb_00006p59
Crystal structure of SIVrcm Vif-CBFbeta-ELOB-ELOC complex
Structural highlights
Disease[PEBB_HUMAN] Note=A chromosomal aberration involving CBFB is associated with acute myeloid leukemia of M4EO subtype. Pericentric inversion inv(16)(p13;q22). The inversion produces a fusion protein that consists of the 165 N-terminal residues of CBF-beta (PEPB2) with the tail region of MYH11. Function[PEBB_HUMAN] CBF binds to the core site, 5'-PYGPYGGT-3', of a number of enhancers and promoters, including murine leukemia virus, polyomavirus enhancer, T-cell receptor enhancers, LCK, IL3 and GM-CSF promoters. CBFB enhances DNA binding by RUNX1. [ELOC_HUMAN] SIII, also known as elongin, is a general transcription elongation factor that increases the RNA polymerase II transcription elongation past template-encoded arresting sites. Subunit A is transcriptionally active and its transcription activity is strongly enhanced by binding to the dimeric complex of the SIII regulatory subunits B and C (elongin BC complex).[1] The elongin BC complex seems to be involved as an adapter protein in the proteasomal degradation of target proteins via different E3 ubiquitin ligase complexes, including the von Hippel-Lindau ubiquitination complex CBC(VHL). By binding to BC-box motifs it seems to link target recruitment subunits, like VHL and members of the SOCS box family, to Cullin/RBX1 modules that activate E2 ubiquitination enzymes.[2] [ELOB_HUMAN] SIII, also known as elongin, is a general transcription elongation factor that increases the RNA polymerase II transcription elongation past template-encoded arresting sites. Subunit A is transcriptionally active and its transcription activity is strongly enhanced by binding to the dimeric complex of the SIII regulatory subunits B and C (elongin BC complex).[3] [4] The elongin BC complex seems to be involved as an adapter protein in the proteasomal degradation of target proteins via different E3 ubiquitin ligase complexes, including the von Hippel-Lindau ubiquitination complex CBC(VHL). By binding to BC-box motifs it seems to link target recruitment subunits, like VHL and members of the SOCS box family, to Cullin/RBX1 modules that activate E2 ubiquitination enzymes.[5] [6] Publication Abstract from PubMedPrimate lentiviruses encode a Vif protein that counteracts the host antiviral APOBEC3 (A3) family members. The adaptation of Vif to species-specific A3 determinants is a critical event that allowed the spillover of a lentivirus from monkey reservoirs to chimpanzees and subsequently to humans, which gave rise to HIV-1 and the acquired immune deficiency syndrome (AIDS) pandemic. How Vif-A3 protein interactions are remodeled during evolution is unclear. Here, we report a 2.94 A crystal structure of the Vif substrate receptor complex from simian immunodeficiency virus isolated from red-capped mangabey (SIVrcm). The structure of the SIVrcm Vif complex illuminates the stage of lentiviral Vif evolution that is immediately prior to entering hominid primates. Structure-function studies reveal the adaptations that allowed SIVrcm Vif to antagonize hominid A3G. These studies show a partitioning between an evolutionarily dynamic specificity determinant and a conserved protein interacting surface on Vif that enables adaptation while maintaining protein interactions required for potent A3 antagonism. Structural Basis for a Species-Specific Determinant of an SIV Vif Protein toward Hominid APOBEC3G Antagonism.,Binning JM, Chesarino NM, Emerman M, Gross JD Cell Host Microbe. 2019 Dec 11;26(6):739-747.e4. doi: 10.1016/j.chom.2019.10.014. PMID:31830442[7] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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