1xcb
From Proteopedia
(New page: 200px<br /><applet load="1xcb" size="450" color="white" frame="true" align="right" spinBox="true" caption="1xcb, resolution 2.9Å" /> '''X-ray Structure of a ...) |
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| - | [[Image:1xcb.jpg|left|200px]]<br /><applet load="1xcb" size=" | + | [[Image:1xcb.jpg|left|200px]]<br /><applet load="1xcb" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1xcb, resolution 2.9Å" /> | caption="1xcb, resolution 2.9Å" /> | ||
'''X-ray Structure of a Rex-Family Repressor/NADH Complex from Thermus Aquaticus'''<br /> | '''X-ray Structure of a Rex-Family Repressor/NADH Complex from Thermus Aquaticus'''<br /> | ||
==Overview== | ==Overview== | ||
| - | The redox-sensing repressor Rex regulates transcription of respiratory | + | The redox-sensing repressor Rex regulates transcription of respiratory genes in response to the intra cellular NADH/NAD(+) redox poise. As a step toward elucidating the molecular mechanism of NADH/NAD(+) sensing, the X-ray structure of Thermus aquaticus Rex (T-Rex) bound to effector NADH has been determined at 2.9 A resolution. The fold of the C-terminal domain of T-Rex is characteristic of NAD(H)-dependent enzymes, whereas the N-terminal domain is similar to a winged helix DNA binding motif. T-Rex dimerization is primarily mediated by "domain-swapped" alpha helices. Each NADH molecule binds to the C-terminal domain near the dimer interface. In contrast to NAD(H)-dependent enzymes, the nicotinamide is deeply buried within a hydrophobic pocket that appears to preclude substrate entry. We show that T-Rex binds to the Rex operator, and NADH but not NAD(+) inhibits T-Rex/DNA binding activity. A mechanism for redox sensing by Rex family members is proposed by analogy with domain closure of NAD(H)-dependent enzymes. |
==About this Structure== | ==About this Structure== | ||
| - | 1XCB is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Thermus_aquaticus Thermus aquaticus] with CA and NAD as [http://en.wikipedia.org/wiki/ligands ligands]. This structure | + | 1XCB is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Thermus_aquaticus Thermus aquaticus] with <scene name='pdbligand=CA:'>CA</scene> and <scene name='pdbligand=NAD:'>NAD</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. This structure supersedes the now removed PDB entry 1R72. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1XCB OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Thermus aquaticus]] | [[Category: Thermus aquaticus]] | ||
| - | [[Category: Bonanno, J | + | [[Category: Bonanno, J B.]] |
[[Category: Brekasis, D.]] | [[Category: Brekasis, D.]] | ||
| - | [[Category: Burley, S | + | [[Category: Burley, S K.]] |
| - | [[Category: Kielkopf, C | + | [[Category: Kielkopf, C L.]] |
| - | [[Category: NYSGXRC, New | + | [[Category: NYSGXRC, New York Structural GenomiX Research Consortium.]] |
| - | [[Category: Paget, M | + | [[Category: Paget, M S.]] |
[[Category: Paranawithana, S.]] | [[Category: Paranawithana, S.]] | ||
| - | [[Category: Sickmier, E | + | [[Category: Sickmier, E A.]] |
[[Category: CA]] | [[Category: CA]] | ||
[[Category: NAD]] | [[Category: NAD]] | ||
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[[Category: winged helix]] | [[Category: winged helix]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 15:53:15 2008'' |
Revision as of 13:53, 21 February 2008
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X-ray Structure of a Rex-Family Repressor/NADH Complex from Thermus Aquaticus
Overview
The redox-sensing repressor Rex regulates transcription of respiratory genes in response to the intra cellular NADH/NAD(+) redox poise. As a step toward elucidating the molecular mechanism of NADH/NAD(+) sensing, the X-ray structure of Thermus aquaticus Rex (T-Rex) bound to effector NADH has been determined at 2.9 A resolution. The fold of the C-terminal domain of T-Rex is characteristic of NAD(H)-dependent enzymes, whereas the N-terminal domain is similar to a winged helix DNA binding motif. T-Rex dimerization is primarily mediated by "domain-swapped" alpha helices. Each NADH molecule binds to the C-terminal domain near the dimer interface. In contrast to NAD(H)-dependent enzymes, the nicotinamide is deeply buried within a hydrophobic pocket that appears to preclude substrate entry. We show that T-Rex binds to the Rex operator, and NADH but not NAD(+) inhibits T-Rex/DNA binding activity. A mechanism for redox sensing by Rex family members is proposed by analogy with domain closure of NAD(H)-dependent enzymes.
About this Structure
1XCB is a Single protein structure of sequence from Thermus aquaticus with and as ligands. This structure supersedes the now removed PDB entry 1R72. Full crystallographic information is available from OCA.
Reference
X-ray structure of a Rex-family repressor/NADH complex insights into the mechanism of redox sensing., Sickmier EA, Brekasis D, Paranawithana S, Bonanno JB, Paget MS, Burley SK, Kielkopf CL, Structure. 2005 Jan;13(1):43-54. PMID:15642260
Page seeded by OCA on Thu Feb 21 15:53:15 2008
Categories: Single protein | Thermus aquaticus | Bonanno, J B. | Brekasis, D. | Burley, S K. | Kielkopf, C L. | NYSGXRC, New York Structural GenomiX Research Consortium. | Paget, M S. | Paranawithana, S. | Sickmier, E A. | CA | NAD | Nad | New york structural genomix research consortium | Nicotinamide adenine dinucleotide | Nysgxrc | Protein structure initiative | Psi | Redox-sensing | Rex | Rossmann fold | Structural genomics | Winged helix
