3UPU

Crystal structure of the T4 Phage SF1B Helicase Dda

Summary for 3UPU

• Entry DOI: 10.2210/pdb3upu/pdb
• Descriptor: ATP-dependent DNA helicase dda, 5'-D(*TP*TP*TP*TP*TP*TP*TP*T)-3' (3 entities in total)
• Functional Keywords: reca-like domain, sh3 domain, pin-tower interface, coupling atp hydrolysis to dna unwinding, ssdna, hydrolase-dna complex, hydrolase/dna
• Biological source: Enterobacteria phage T4
• Total number of polymer chains: 6
• Total formula weight: 164652.91

Authors

He, X.,Yun, M.K.,Pemble IV, C.W.,Kreuzer, K.N.,Raney, K.D.,White, S.W. (deposition date: 2011-11-18, release date: 2012-06-20, Last modification date: 2024-10-16)

Primary citation

He, X.,Byrd, A.K.,Yun, M.K.,Pemble, C.W.,Harrison, D.,Yeruva, L.,Dahl, C.,Kreuzer, K.N.,Raney, K.D.,White, S.W.
The T4 Phage SF1B Helicase Dda Is Structurally Optimized to Perform DNA Strand Separation.
Structure, 20:1189-1200, 2012

PubMed Abstract: Helicases move on DNA via an ATP binding and hydrolysis mechanism coordinated by well-characterized helicase motifs. However, the translocation along single-stranded DNA (ssDNA) and the strand separation of double-stranded (dsDNA) may be loosely or tightly coupled. Dda is a phage T4 SF1B helicase with sequence homology to the Pif1 family of helicases that tightly couples translocation to strand separation. The crystal structure of the Dda-ssDNA binary complex reveals a domain referred to as the "pin" that was previously thought to remain static during strand separation. The pin contains a conserved phenylalanine that mediates a transient base-stacking interaction that is absolutely required for separation of dsDNA. The pin is secured at its tip by protein-protein interactions through an extended SH3 domain thereby creating a rigid strut. The conserved interface between the pin and the SH3 domain provides the mechanism for tight coupling of translocation to strand separation.

PubMed: 22658750
DOI: 10.1016/j.str.2012.04.013

Experimental method

X-RAY DIFFRACTION (3.299 Å)