User:Cameron Ball/Sandbox 1: Difference between revisions
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Replication Terminator Protein (RTP) is a protein found in ''Bacillus Subtilis''(''B.Subtilis'') that plays an important role in the termination of bacterial chromosome replication. RTP binds to the circular bacterial genome to block the progression of DNA polymerase in a polar manner. A protein that performs the same function as RTP has been found in ''Eschericia coli'' (''E.coli''), named “Termination Utilisation Substance” (Tus) | Replication Terminator Protein (RTP) is a protein found in ''Bacillus Subtilis''(''B.Subtilis'') that plays an important role in the termination of bacterial chromosome replication. RTP binds to the circular bacterial genome to block the progression of DNA polymerase in a polar manner. A protein that performs the same function as RTP has been found in ''Eschericia coli'' (''E.coli''), named “Termination Utilisation Substance” (Tus) | ||
[[Image:bsubtilisrtpschematic.png|300px|right|thumb| Schematic diagram of the ''B.subtilis'' genome showing clockwise and anticlockwise replication forks and traps. RTP is represented by the red and blue blocks.]] | [[Image:bsubtilisrtpschematic.png|300px|right|thumb| Schematic diagram of the ''B.subtilis'' genome showing clockwise and anticlockwise replication forks and traps. RTP is represented by the red and blue blocks.]] | ||
==Introduction== | ==Introduction== | ||
The bacterial genome of ''B.subtilis'' is circular and contains only one origin of replication (OriC). In order to increase the efficiency of DNA replication, the DNA is copied in clockwise and anticlockwise directions simultaneously and later ligated together. It has been found that many organisms employ a mechanism to aid in this termination, suggesting an evolutionary advantage in possessing such a system <ref>A.A. Griffiths, P.A. Andersen and R.G. Wake, Replication terminator protein-based replication fork-arrest systems in various Bacillus species, J. Bacteriol. 180 (1998), pp. 3360–3367</ref>(although mutants lacking the tus gene are still viable<ref>King, G.F., Wake, R.G., A tale of two terminators: crystal structures sharpen the debate on DNA replication fork arrest mechanisms 1997 '''Structure''' Vol 5 No 1</ref>). | The bacterial genome of ''B.subtilis'' is circular and contains only one origin of replication (OriC). In order to increase the efficiency of DNA replication, the DNA is copied in clockwise and anticlockwise directions simultaneously and later ligated together. It has been found that many organisms employ a mechanism to aid in this termination, suggesting an evolutionary advantage in possessing such a system <ref>A.A. Griffiths, P.A. Andersen and R.G. Wake, Replication terminator protein-based replication fork-arrest systems in various Bacillus species, J. Bacteriol. 180 (1998), pp. 3360–3367</ref>(although mutants lacking the tus gene are still viable<ref>King, G.F., Wake, R.G., A tale of two terminators: crystal structures sharpen the debate on DNA replication fork arrest mechanisms 1997 '''Structure''' Vol 5 No 1</ref>). | ||
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| 23 bp site, no internal symmetry, binds a monomer of tus. | | 23 bp site, no internal symmetry, binds a monomer of tus. | ||
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In 2000, Anderson ''et al'' inserted the ''E.coli'' TerB sequence into a ''B.subtilis'' plasmid and transformed it into a ''B.subtilis'' cell line that could overexpress tus. They found that the Tus-Ter system arrested fork activity in ''B.subtilis'' with approximately 5% efficiency, compared to 45% efficiency in ''E.coli''. They also performed the reverse experiment, by introducing the ''B.subtilis'' RTP-Ter system into ''E.coli''. They found that fork arrest efficiency was approximately 3.2%, about a 3 fold decrease over the native activity in ''B.subtilis'' (10.6%) <ref>Andersen, P., Griffiths, A., Duggin, I., and Wake, R. (2000) Functional specificity of the replication fork-arrest complexes of Bacillus subtilis and Escherichia coli: significant specificity for Tus-Ter functioning in E. coli. Mol Microbiol 36: 1327–1335. </ref> | |||
This once again emphasises the difference of the two systems and also confirms that simple RTP/Tus-Ter contact is not enough to efficiently cause fork arrest. | |||
==References== | ==References== | ||
{{Reflist}} | {{Reflist}} | ||
