1CI4

THE CRYSTAL STRUCTURE OF HUMAN BARRIER-TO-AUTOINTEGRATION FACTOR (BAF)

Summary for 1CI4

• Entry DOI: 10.2210/pdb1ci4/pdb
• Descriptor: PROTEIN (BARRIER-TO-AUTOINTEGRATION FACTOR (BAF)) (2 entities in total)
• Functional Keywords: dna binding protein, retroviral integration, preintegration complex
• Biological source: Homo sapiens (human)
• Total number of polymer chains: 2
• Total formula weight: 20334.75

Authors

Umland, T.C.,Wei, S.-Q.,Craigie, R.,Davies, D.R. (deposition date: 1999-04-07, release date: 2000-08-16, Last modification date: 2024-10-30)

Primary citation

Umland, T.C.,Wei, S.Q.,Craigie, R.,Davies, D.R.
Structural basis of DNA bridging by barrier-to-autointegration factor.
Biochemistry, 39:9130-9138, 2000

PubMed Abstract: Barrier-to-autointegration factor (BAF) is a host cell protein that plays a crucial role in retroviral integration. Preintegration complexes (PICs) stripped of BAF lose their normal integration activity, which can be restored by incubation with purified BAF. BAF bridges double-stranded DNA both intra- and intermolecularly in a non-sequence-specific manner, leading to the formation of a nucleoprotein network. BAF also binds to the nuclear protein lamina-associated polypeptide 2 (LAP2), and is localized with chromatin during interphase and mitosis. The crystal structure of homodimeric human BAF has been determined to 1.9 A resolution. The fold of the BAF monomer resembles that of the second domain of RuvA. This comparison revealed the presence of the helix-hairpin-helix (HhH) nonspecific DNA binding motif within BAF. A novel feature of BAF's HhH motif is the occupation of the metal binding site by the epsilon-amino group of Lys 6, providing an alternative means of sequestering positive charge. Mutational analysis corroborates the HhH motif's prominent role in DNA binding and argues against a previously proposed helix-turn-helix (HTH) binding site located in another region of the monomer. A model of BAF bridging DNA via the HhH motif is proposed.

PubMed: 10924106
DOI: 10.1021/bi000572w

Experimental method

X-RAY DIFFRACTION (1.9 Å)