2IHF

Crystal structure of deletion mutant delta 228-252 R190A of the single-stranded DNA binding protein from Thermus aquaticus

Summary for 2IHF

• Entry DOI: 10.2210/pdb2ihf/pdb
• Related: 1EYG 1SE8 2IHE
• Descriptor: Single-stranded DNA-binding protein (2 entities in total)
• Functional Keywords: single-stranded dna binding protein (ssb), thermophile organism, protein-dna interaction, protein-protein interaction, dna binding protein
• Biological source: Thermus aquaticus
• Total number of polymer chains: 1
• Total formula weight: 27575.05

Authors

Fedorov, R.,Witte, G.,Urbanke, C.,Manstein, D.J.,Curth, U. (deposition date: 2006-09-26, release date: 2007-01-02, Last modification date: 2023-08-30)

Primary citation

Fedorov, R.,Witte, G.,Urbanke, C.,Manstein, D.J.,Curth, U.
3D structure of Thermus aquaticus single-stranded DNA-binding protein gives insight into the functioning of SSB proteins.
Nucleic Acids Res., 34:6708-6717, 2006

PubMed Abstract: In contrast to the majority of tetrameric SSB proteins, the recently discovered SSB proteins from the Thermus/Deinoccus group form dimers. We solved the crystal structures of the SSB protein from Thermus aquaticus (TaqSSB) and a deletion mutant of the protein and show the structure of their ssDNA binding domains to be similar to the structure of tetrameric SSBs. Two conformations accompanied by proline cis-trans isomerization are observed in the flexible C-terminal region. For the first time, we were able to trace 6 out of 10 amino acids at the C-terminus of an SSB protein. This highly conserved region is essential for interaction with other proteins and we show it to adopt an extended conformation devoid of secondary structure. A model for binding this region to the chi subunit of DNA polymerase III is proposed. It explains at a molecular level the reason for the ssb113 phenotype observed in Escherichia coli.

PubMed: 17148487
DOI: 10.1093/nar/gkl1002

Experimental method

X-RAY DIFFRACTION (1.9 Å)