Structural highlights
Function[TUS_ECOLI] Trans-acting protein required for termination of DNA replication. Binds to DNA replication terminator sequences (terA to terF) to prevent the passage of replication forks. The termination efficiency will be affected by the affinity of this protein for the terminator sequence. Publication Abstract from PubMedThe structure of a 22 amino acid peptide, TPPI [Nedved, M. L., Gottlieb, P. A., & Moe, G. R. (1994) Nucleic Acids Res. 22, 5024-5030], that is similar to the proline repeat segment of the replication arrest protein, Tus, has been determined by 1H NMR in 50% trifluroethanol. The structure is a novel left-handed helix having 5.56 residues per turn and a regular hydrogen bonding network that is limited to one side of the helix and contains a channel that runs down the helix axis. The latter feature gives the structure an overall pipe-like appearance; hence, the structure has been designated a proline pipe helix. The Tus proline pipe is also amphiphilic with one side consisting of proline and other nonpolar residues while the other side contains mostly basic and other polar residues. Tus and several other proteins that contain a similar proline repeat sequence are DNA binding proteins. It is shown here that the proline pipe helix of TPPI can be accommodated within the major grove of B-form DNA in a manner that positions nearly all of the basic residues near phosphate groups in the DNA backbone. The proline pipe helical motif may be a structural element of many other proteins including integral membrane receptor proteins. Proline pipe helix: structure of the tus proline repeat determined by 1H NMR.,Butcher DJ, Nedved ML, Neiss TG, Moe GR Biochemistry. 1996 Jan 23;35(3):698-703. PMID:8547250[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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