Replication terminator Tus family (original) (raw)

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Protein family

Ter
Nmr study of the proline repeat from tus
Identifiers
Symbol Ter
Pfam PF05472
InterPro IPR008865
SCOP2 5eau / SCOPe / SUPFAM
Available protein structures:Pfam structures / ECOD PDBRCSB PDB; PDBe; PDBjPDBsumstructure summary

Representation of the x-ray crystal structure of Tus-Ter protein-DNA complex. (Jmol rendering of coordinates from.[1] The DNA strands are shown in pink and green.)

Tus (terminus utilization substance), also known as a ter-binding protein, is a protein that binds to terminator sequences and acts as a counter-helicase when it comes in contact with an advancing helicase.[2] The bound Tus protein effectively halts DNA polymerase movement.[2] Tus helps end DNA replication in prokaryotes.[2] They function by binding to DNA replication terminator sequences, thus preventing the passage of replication forks.[3] The termination efficiency is affected by the affinity of a particular protein for the terminator sequence.

In E. coli (P16525), Tus binds to 10 closely related sites encoded in the chromosome, although only 6 are likely to be involved in replication termination. Each site is 23 base pairs. The sites are called Ter sites, and are designated TerA, TerB, ..., TerG. These binding sites are asymmetric, such that when a Tus-Ter complex (Tus protein bound to a Ter site) is encountered by a replication fork from one direction, the complex is dissociated and replication continues (permissive). But when encountered from the other direction, the Tus-Ter complex provides a much larger kinetic barrier and halts replication (non-permissive). The multiple Ter sites in the chromosome are oriented such that the two oppositely moving replication forks are both stalled in the desired termination region.[4]

Bacillus subtilis utilize replication terminator protein (RTP) instead of Tus. This is a different protein family using a different structure to bind to DNA: InterPro: IPR003432.

The Ter protein contains two domains. The N-terminal domain is composed of an alpha helices, beta sheet, and three loops. The C-terminal domain is made of two alpha helices and one beta sheet.[5] Alternatively, CATH divides the structure into a big domain spanning the entire sequence and a small insertion that pops out and folds as a separate domain.[6]

A DNA replication terminus (Ter) has a role in preventing progress of the DNA replication fork.[7] Therefore, a DNA replication terminus site-binding protein binds to this site helping to block the DNA replication fork. There are two genes controlling Ter-binding activity, named tau and Tus.[3]

  1. ^ a b Kamada, K.; Horiuchi, T.; Ohsumi, K.; Shimamoto, N.; Morikawa, K. (1996). "Structure of a replication-terminator protein complexed with DNA". Nature. 383 (6601): 598–603. Bibcode:1996Natur.383..598K. doi:10.1038/383598a0. PMID 8857533.
  2. ^ a b c Slonczewski, Joan, and John Watkins. Foster. Microbiology: An Evolving Science. New York: W.W. Norton &, 2009. Print.
  3. ^ a b Hidaka M, Kobayashi T, Takenaka S, Takeya H, Horiuchi T (December 1989). "Purification of a DNA replication terminus (ter) site-binding protein in Escherichia coli and identification of the structural gene". J. Biol. Chem. 264 (35): 21031–7. doi:10.1016/S0021-9258(19)30040-7. PMID 2687269.
  4. ^ a b Mulcair, M.; Schaeffer, P.; Oakley, A.; Cross, H.; Neylon, C.; Hill, T.; Dixon, N. (2006). "A Molecular Mousetrap Determines Polarity of Termination of DNA Replication in E. Coli". Cell. 125 (7): 1309–1319. doi:10.1016/j.cell.2006.04.040. PMID 16814717.
  5. ^ Kamada K, Horiuchi T, Ohsumi K, Shimamoto N, Morikawa K (1996). "Structure of a replication-terminator protein complexed with DNA". Nature. 383 (6601): 598–603. Bibcode:1996Natur.383..598K. doi:10.1038/383598a0. PMID 8857533.
  6. ^ "TED: The Encyclopedia of Domains". ted.cathdb.info.
  7. ^ Hidaka M, Kobayashi T, Horiuchi T (1991). "A newly identified DNA replication terminus site, TerE, on the Escherichia coli chromosome". J Bacteriol. 173 (1): 391–3. doi:10.1128/jb.173.1.391-393.1991. PMC 207198. PMID 1824765.
  8. ^ Neylon; Brown, S. E.; Kralicek, A. V.; Miles, C. S.; Love, C. A.; Dixon, N. E. (2000). "Interaction of the Escherichia coli replication terminator protein (Tus) with DNA: a model derived from DNA-binding studies of mutant proteins by surface plasmon resonance" (PDF). Biochemistry. 39 (39): 11989–11999. doi:10.1021/bi001174w. PMID 11009613.
  9. ^ Neylon, C.; Kralicek, A. V.; Hill, T. M.; Dixon, N. E. (2005). "Replication Termination in Escherichia coli: Structure and Antihelicase Activity of the Tus-Ter Complex". Microbiology and Molecular Biology Reviews. 69 (3): 501–26. doi:10.1128/MMBR.69.3.501-526.2005. PMC 1197808. PMID 16148308.
  10. ^ Skokotas; Wrobleski, M.; Hill, T. M. (1994). "Isolation and characterization of mutants of Tus, the replication arrest protein of Escherichia coli". The Journal of Biological Chemistry. 269 (32): 20446–20455. doi:10.1016/S0021-9258(17)32013-6. PMID 8051142.
  11. ^ Coskun-ari; Skokotas, A.; Moe, G. R.; Hill, T. M. (1994). "Biophysical characteristics of Tus, the replication arrest protein of Escherichia coli". The Journal of Biological Chemistry. 269 (6): 4027–4034. doi:10.1016/S0021-9258(17)41737-6. PMID 8307958.