5jw9

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The Crystal Structure of ELL2 Oclludin Domain and AFF4 peptide

Structural highlights

5jw9 is a 2 chain structure with sequence from Homo sapiens. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:	X-ray diffraction, Resolution 2.003Å
Ligands:
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Disease

AFF4_HUMAN Note=A chromosomal aberration involving AFF4 is found in acute lymphoblastic leukemia (ALL). Insertion ins(5;11)(q31;q13q23) that forms a MLL-AFF4 fusion protein.

Function

AFF4_HUMAN Key component of the super elongation complex (SEC), a complex required to increase the catalytic rate of RNA polymerase II transcription by suppressing transient pausing by the polymerase at multiple sites along the DNA. In the SEC complex, AFF4 acts as a central scaffold that recruits other factors through direct interactions with ELL proteins (ELL, ELL2 or ELL3) and the P-TEFb complex. In case of infection by HIV-1 virus, the SEC complex is recruited by the viral Tat protein to stimulate viral gene expression.^[1] ^[2] ^[3]

Publication Abstract from PubMed

The intrinsically disordered scaffold proteins AFF1/4 and the transcription elongation factors ELL1/2 are core components of the super elongation complex required for HIV-1 proviral transcription. Here we report the 2.0-A resolution crystal structure of the human ELL2 C-terminal domain bound to its 50-residue binding site on AFF4, the ELLBow. The ELL2 domain has the same arch-shaped fold as the tight junction protein occludin. The ELLBow consists of an N-terminal helix followed by an extended hairpin that we refer to as the elbow joint, and occupies most of the concave surface of ELL2. This surface is important for the ability of ELL2 to promote HIV-1 Tat-mediated proviral transcription. The AFF4-ELL2 interface is imperfectly packed, leaving a cavity suggestive of a potential binding site for transcription-promoting small molecules.

Structural basis for ELL2 and AFF4 activation of HIV-1 proviral transcription.,Qi S, Li Z, Schulze-Gahmen U, Stjepanovic G, Zhou Q, Hurley JH Nat Commun. 2017 Jan 30;8:14076. doi: 10.1038/ncomms14076. PMID:28134250^[4]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ He N, Liu M, Hsu J, Xue Y, Chou S, Burlingame A, Krogan NJ, Alber T, Zhou Q. HIV-1 Tat and host AFF4 recruit two transcription elongation factors into a bifunctional complex for coordinated activation of HIV-1 transcription. Mol Cell. 2010 May 14;38(3):428-38. doi: 10.1016/j.molcel.2010.04.013. PMID:20471948 doi:10.1016/j.molcel.2010.04.013
↑ Lin C, Smith ER, Takahashi H, Lai KC, Martin-Brown S, Florens L, Washburn MP, Conaway JW, Conaway RC, Shilatifard A. AFF4, a component of the ELL/P-TEFb elongation complex and a shared subunit of MLL chimeras, can link transcription elongation to leukemia. Mol Cell. 2010 Feb 12;37(3):429-37. doi: 10.1016/j.molcel.2010.01.026. PMID:20159561 doi:10.1016/j.molcel.2010.01.026
↑ Chou S, Upton H, Bao K, Schulze-Gahmen U, Samelson AJ, He N, Nowak A, Lu H, Krogan NJ, Zhou Q, Alber T. HIV-1 Tat recruits transcription elongation factors dispersed along a flexible AFF4 scaffold. Proc Natl Acad Sci U S A. 2013 Jan 8;110(2):E123-31. doi:, 10.1073/pnas.1216971110. Epub 2012 Dec 18. PMID:23251033 doi:10.1073/pnas.1216971110
↑ Qi S, Li Z, Schulze-Gahmen U, Stjepanovic G, Zhou Q, Hurley JH. Structural basis for ELL2 and AFF4 activation of HIV-1 proviral transcription. Nat Commun. 2017 Jan 30;8:14076. doi: 10.1038/ncomms14076. PMID:28134250 doi:http://dx.doi.org/10.1038/ncomms14076