Download Mendeley3D structure of Thermus aquaticus single-stranded DNA-binding protein gives insight into the functioning of SSB proteins.
Fedorov, R., Witte, G., Urbanke, C., Manstein, D.J., Curth, U.(2006) Nucleic Acids Res 34: 6708-6717
- PubMed: 17148487
- DOI: https://doi.org/10.1093/nar/gkl1002
- Primary Citation of Related Structures:
2IHE, 2IHF - 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.
Organizational Affiliation:
Institute for Biophysical Chemistry, Hannover Medical Schoo,l Carl-Neuberg-Strasse 1, D-30625 Hannover, Germany.
