Logo image
Back
Crystal structure of HIV-1 Tat complexed with human P-TEFb and AFF4
Journal article   Open access   Peer reviewed

Crystal structure of HIV-1 Tat complexed with human P-TEFb and AFF4

Jianyou Gu, Nigar D Babayeva, Yoshiaki Suwa, Andrey G Baranovskiy, David H Price and Tahir H Tahirov
Cell cycle (Georgetown, Tex.), Vol.13(11), pp.1788-1797
2014
DOI: 10.4161/cc.28756
PMCID: PMC4111725
PMID: 24727379
url
https://doi.org/10.4161/cc.28756View
Published (Version of record) Open Access

Abstract

Developing anti-viral therapies targeting HIV-1 transcription has been hampered by the limited structural knowledge of the proteins involved. HIV-1 hijacks the cellular machinery that controls RNA polymerase II elongation through an interaction of HIV-1 Tat with the positive transcription elongation factor P-TEFb, which interacts with an AF4 family member (AFF1/2/3/4) in the super elongation complex (SEC). Because inclusion of Tat•P-TEFb into the SEC is critical for HIV transcription, we have determined the crystal structure of the Tat•AFF4•P-TEFb complex containing HIV-1 Tat (residues 1-48), human Cyclin T1 (1-266), human Cdk9 (7-332), and human AFF4 (27-69). Tat binding to AFF4•P-TEFb causes concerted structural changes in AFF4 via a shift of helix H5' of Cyclin T1 and the α-3 10 helix of AFF4. The interaction between Tat and AFF4 provides structural constraints that explain tolerated Tat mutations. Analysis of the Tat-binding surface of AFF4 coupled with modeling of all other AF4 family members suggests that AFF1 and AFF4 would be preferred over AFF2 or AFF3 for interaction with Tat•P-TEFb. The structure establishes that the Tat-TAR recognition motif (TRM) in Cyclin T1 interacts with both Tat and AFF4, leading to the exposure of arginine side chains for binding to TAR RNA. Furthermore, modeling of Tat Lys28 acetylation suggests that the acetyl group would be in a favorable position for H-bond formation with Asn257 of TRM, thereby stabilizing the TRM in Cyclin T1, and provides a structural basis for the modulation of TAR RNA binding by acetylation of Tat Lys28.
 Acetylation Crystallization Cyclin T - chemistry Cyclin T - metabolism Cyclin-Dependent Kinase 9 - chemistry Cyclin-Dependent Kinase 9 - metabolism HIV-1 - chemistry Humans Models, Molecular Multiprotein Complexes - chemistry Multiprotein Complexes - metabolism Positive Transcriptional Elongation Factor B - chemistry Positive Transcriptional Elongation Factor B - metabolism Protein Conformation Repressor Proteins - chemistry Repressor Proteins - metabolism tat Gene Products, Human Immunodeficiency Virus - chemistry tat Gene Products, Human Immunodeficiency Virus - metabolism Transcriptional Elongation Factors

Details

Metrics

14 Record Views
49 Times Cited - Web of Science
Logo image