2g9e: Difference between revisions

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[[Image:2g9e.gif|left|200px]]<br /><applet load="2g9e" size="~~450~~" color="white" frame="true" align="right" spinBox="true"

[[Image:2g9e.gif|left|200px]]<br /><applet load="2g9e" size="350" color="white" frame="true" align="right" spinBox="true"

caption="2g9e, resolution 1.80Å" />

'''Protonation-mediated structural flexibility in the F conjugation regulatory protein, TRAM'''<br />

==Overview==

TraM is essential for F plasmid-mediated bacterial conjugation, where it, binds to the plasmid DNA near the origin of transfer, and recognizes a, component of the transmembrane DNA transfer complex, TraD. Here we report, the 1.40 A crystal structure of the TraM core tetramer (TraM58-127)., TraM58-127 is a compact eight-helical bundle, in which the N-terminal, helices from each protomer interact to form a central, parallel, four-stranded coiled-coil, whereas each C-terminal helix packs in an, antiparallel arrangement around the outside of the structure. Four, protonated glutamic acid residues (Glu88) are packed in a hydrogen-bonded, arrangement within the central four-helix bundle. Mutational and, biophysical analyses indicate that this protonated state is in equilibrium, with a deprotonated tetrameric form characterized by a lower helical, content at physiological pH and temperature. Comparison of TraM to its, Glu88 mutants predicted to stabilize the helical structure suggests that, the protonated state is the active form for binding TraD in conjugation.

TraM is essential for F plasmid-mediated bacterial conjugation, where it binds to the plasmid DNA near the origin of transfer, and recognizes a component of the transmembrane DNA transfer complex, TraD. Here we report the 1.40 A crystal structure of the TraM core tetramer (TraM58-127). TraM58-127 is a compact eight-helical bundle, in which the N-terminal helices from each protomer interact to form a central, parallel four-stranded coiled-coil, whereas each C-terminal helix packs in an antiparallel arrangement around the outside of the structure. Four protonated glutamic acid residues (Glu88) are packed in a hydrogen-bonded arrangement within the central four-helix bundle. Mutational and biophysical analyses indicate that this protonated state is in equilibrium with a deprotonated tetrameric form characterized by a lower helical content at physiological pH and temperature. Comparison of TraM to its Glu88 mutants predicted to stabilize the helical structure suggests that the protonated state is the active form for binding TraD in conjugation.

==About this Structure==

2G9E is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Full crystallographic information is available from [http://~~ispc~~.weizmann.ac.il/oca-bin/ocashort?id=2G9E OCA].

2G9E is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2G9E OCA].

==Reference==

Line 13:

[[Category: Escherichia coli]]

[[Category: Single protein]]

[[Category: Edwards, R.A.]]

[[Category: Edwards, R A.]]

[[Category: Frost, L.S.]]

[[Category: Frost, L S.]]

[[Category: Glover, J.N.]]

[[Category: Glover, J N.]]

[[Category: Lu, J.]]

[[Category: Manchak, J.]]

[[Category: Scott, P.G.]]

[[Category: Scott, P G.]]

[[Category: Wong, J.J.]]

[[Category: Wong, J J.]]

[[Category: e88l mutant]]

[[Category: four helix bundle]]

[[Category: tetramer]]

''Page seeded by [http://~~ispc~~.weizmann.ac.il/oca OCA ] on ~~Wed Nov~~ 21 11:03:~~10 2007~~''

''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 17:29:26 2008''

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@@ Line 1: / Line 1: @@
-[[Image:2g9e.gif|left|200px]]<br /><applet load="2g9e" size="450" color="white" frame="true" align="right" spinBox="true"
+[[Image:2g9e.gif|left|200px]]<br /><applet load="2g9e" size="350" color="white" frame="true" align="right" spinBox="true"
 caption="2g9e, resolution 1.80&Aring;" />
 '''Protonation-mediated structural flexibility in the F conjugation regulatory protein, TRAM'''<br />
 ==Overview==
-TraM is essential for F plasmid-mediated bacterial conjugation, where it, binds to the plasmid DNA near the origin of transfer, and recognizes a, component of the transmembrane DNA transfer complex, TraD. Here we report, the 1.40 A crystal structure of the TraM core tetramer (TraM58-127)., TraM58-127 is a compact eight-helical bundle, in which the N-terminal, helices from each protomer interact to form a central, parallel, four-stranded coiled-coil, whereas each C-terminal helix packs in an, antiparallel arrangement around the outside of the structure. Four, protonated glutamic acid residues (Glu88) are packed in a hydrogen-bonded, arrangement within the central four-helix bundle. Mutational and, biophysical analyses indicate that this protonated state is in equilibrium, with a deprotonated tetrameric form characterized by a lower helical, content at physiological pH and temperature. Comparison of TraM to its, Glu88 mutants predicted to stabilize the helical structure suggests that, the protonated state is the active form for binding TraD in conjugation.
+TraM is essential for F plasmid-mediated bacterial conjugation, where it binds to the plasmid DNA near the origin of transfer, and recognizes a component of the transmembrane DNA transfer complex, TraD. Here we report the 1.40 A crystal structure of the TraM core tetramer (TraM58-127). TraM58-127 is a compact eight-helical bundle, in which the N-terminal helices from each protomer interact to form a central, parallel four-stranded coiled-coil, whereas each C-terminal helix packs in an antiparallel arrangement around the outside of the structure. Four protonated glutamic acid residues (Glu88) are packed in a hydrogen-bonded arrangement within the central four-helix bundle. Mutational and biophysical analyses indicate that this protonated state is in equilibrium with a deprotonated tetrameric form characterized by a lower helical content at physiological pH and temperature. Comparison of TraM to its Glu88 mutants predicted to stabilize the helical structure suggests that the protonated state is the active form for binding TraD in conjugation.
 ==About this Structure==
-G9E is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=2G9E OCA].
+G9E is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2G9E OCA].
 ==Reference==
@@ Line 13: / Line 13: @@
 [[Category: Escherichia coli]]
 [[Category: Single protein]]
-[[Category: Edwards, R.A.]]
+[[Category: Edwards, R A.]]
-[[Category: Frost, L.S.]]
+[[Category: Frost, L S.]]
-[[Category: Glover, J.N.]]
+[[Category: Glover, J N.]]
 [[Category: Lu, J.]]
 [[Category: Manchak, J.]]
-[[Category: Scott, P.G.]]
+[[Category: Scott, P G.]]
-[[Category: Wong, J.J.]]
+[[Category: Wong, J J.]]
 [[Category: e88l mutant]]
 [[Category: four helix bundle]]
 [[Category: tetramer]]
-''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Wed Nov 21 11:03:10 2007''
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 17:29:26 2008''