User:Cameron Ball/Sandbox 1: Difference between revisions
From Proteopedia
Jump to navigationJump to search
Cameron Ball (talk | contribs) mNo edit summary |
Cameron Ball (talk | contribs) mNo edit summary |
||
| Line 1: | Line 1: | ||
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 | 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> | 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 Termination Sites== | ==The Termination Sites== | ||
| Line 20: | Line 20: | ||
==Comparison of Tus and RTP== | ==Comparison of Tus and RTP== | ||
As previously mentioned, ''E.coli'' express a protein called tus that performs an almost identical function to RTP. Despite the similarity of their purpose, the underlying mechanism of action and 3D structure are markedly different. This suggests that these two systems evolved separately to each other, once again highlighting their importance <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 differences between the two proteins are summarised below. | |||
{| class="wikitable" | {| class="wikitable" | ||
| Line 28: | Line 29: | ||
|- | |- | ||
| '''Structure''' | | '''Structure''' | ||
| Binds as a symmetrical dimer | |style=white-space:nowrap|Binds as a symmetrical dimer | ||
| Binds as an asymetrical monomer | | Binds as an asymetrical monomer | ||
|- | |- | ||
| Line 38: | Line 39: | ||
| Binds to ''Ter'' site directionally, bends DNA and may contact DnaB protein directly to inhibit DNA melting | | Binds to ''Ter'' site directionally, bends DNA and may contact DnaB protein directly to inhibit DNA melting | ||
| Contacts DnaB to halt it's translocation along DNA <ref> Kaplan, D.L and Bastia, D, Mechanisms of polar arrest of a replication fork, Molecular Microbiology 2009:72:2), pp 279-285 </ref> | | Contacts DnaB to halt it's translocation along DNA <ref> Kaplan, D.L and Bastia, D, Mechanisms of polar arrest of a replication fork, Molecular Microbiology 2009:72:2), pp 279-285 </ref> | ||
|- | |||
| '''''Ter'' Site''' | |||
| 29 bp site, contains two 16bp non-identical inverted repeats (A and B sites) that share a 3 base pair overlap, each site binds a dimer of RTP | |||
| 23 bp site, no internal symmetry, binds a monomer of tus. | |||
|} | |} | ||
==References== | ==References== | ||
{{Reflist}} | {{Reflist}} | ||
