1ntm

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(New page: 200px<br /><applet load="1ntm" size="450" color="white" frame="true" align="right" spinBox="true" caption="1ntm, resolution 2.40&Aring;" /> '''Crystal Structure of...)
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caption="1ntm, resolution 2.40&Aring;" />
'''Crystal Structure of Mitochondrial Cytochrome bc1 Complex at 2.4 Angstrom'''<br />
'''Crystal Structure of Mitochondrial Cytochrome bc1 Complex at 2.4 Angstrom'''<br />
==Overview==
==Overview==
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Cytochrome bc(1) is an integral membrane protein complex essential to, cellular respiration and photosynthesis. The Q cycle reaction mechanism of, bc(1) postulates a separated quinone reduction (Q(i)) and quinol oxidation, (Q(o)) site. In a complete catalytic cycle, a quinone molecule at the Q(i), site receives two electrons from the b(H) heme and two protons from the, negative side of the membrane; this process is specifically inhibited by, antimycin A and NQNO. The structures of bovine mitochondrial bc(1) in the, presence or absence of bound substrate ubiquinone and with either the, bound antimycin A(1) or NQNO were determined and refined. A ubiquinone, with its first two isoprenoid repeats and an antimycin A(1) were, identified in the Q(i) pocket of the substrate and inhibitor bound, structures, respectively; the NQNO, on the other hand, was identified in, both Q(i) and Q(o) pockets in the inhibitor complex. The two inhibitors, occupied different portions of the Q(i) pocket and competed with substrate, for binding. In the Q(o) pocket, the NQNO behaves similarly to, stigmatellin, inducing an iron-sulfur protein conformational arrest., Extensive binding interactions and conformational adjustments of residues, lining the Q(i) pocket provide a structural basis for the high affinity, binding of antimycin A and for phenotypes of inhibitor resistance. A, two-water-mediated ubiquinone protonation mechanism is proposed involving, three Q(i) site residues His(201), Lys(227), and Asp(228).
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Cytochrome bc(1) is an integral membrane protein complex essential to cellular respiration and photosynthesis. The Q cycle reaction mechanism of bc(1) postulates a separated quinone reduction (Q(i)) and quinol oxidation (Q(o)) site. In a complete catalytic cycle, a quinone molecule at the Q(i) site receives two electrons from the b(H) heme and two protons from the negative side of the membrane; this process is specifically inhibited by antimycin A and NQNO. The structures of bovine mitochondrial bc(1) in the presence or absence of bound substrate ubiquinone and with either the bound antimycin A(1) or NQNO were determined and refined. A ubiquinone with its first two isoprenoid repeats and an antimycin A(1) were identified in the Q(i) pocket of the substrate and inhibitor bound structures, respectively; the NQNO, on the other hand, was identified in both Q(i) and Q(o) pockets in the inhibitor complex. The two inhibitors occupied different portions of the Q(i) pocket and competed with substrate for binding. In the Q(o) pocket, the NQNO behaves similarly to stigmatellin, inducing an iron-sulfur protein conformational arrest. Extensive binding interactions and conformational adjustments of residues lining the Q(i) pocket provide a structural basis for the high affinity binding of antimycin A and for phenotypes of inhibitor resistance. A two-water-mediated ubiquinone protonation mechanism is proposed involving three Q(i) site residues His(201), Lys(227), and Asp(228).
==About this Structure==
==About this Structure==
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1NTM is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Bos_taurus Bos taurus] with HEM and FES as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Ubiquinol--cytochrome-c_reductase Ubiquinol--cytochrome-c reductase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.10.2.2 1.10.2.2] Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1NTM OCA].
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1NTM is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Bos_taurus Bos taurus] with <scene name='pdbligand=HEM:'>HEM</scene> and <scene name='pdbligand=FES:'>FES</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Ubiquinol--cytochrome-c_reductase Ubiquinol--cytochrome-c reductase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.10.2.2 1.10.2.2] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1NTM OCA].
==Reference==
==Reference==
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[[Category: structure]]
[[Category: structure]]
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''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Tue Nov 20 22:32:43 2007''
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''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 14:09:52 2008''

Revision as of 12:09, 21 February 2008

Image:1ntm.gif

1ntm, resolution 2.40Å

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Crystal Structure of Mitochondrial Cytochrome bc1 Complex at 2.4 Angstrom

Overview

Cytochrome bc(1) is an integral membrane protein complex essential to cellular respiration and photosynthesis. The Q cycle reaction mechanism of bc(1) postulates a separated quinone reduction (Q(i)) and quinol oxidation (Q(o)) site. In a complete catalytic cycle, a quinone molecule at the Q(i) site receives two electrons from the b(H) heme and two protons from the negative side of the membrane; this process is specifically inhibited by antimycin A and NQNO. The structures of bovine mitochondrial bc(1) in the presence or absence of bound substrate ubiquinone and with either the bound antimycin A(1) or NQNO were determined and refined. A ubiquinone with its first two isoprenoid repeats and an antimycin A(1) were identified in the Q(i) pocket of the substrate and inhibitor bound structures, respectively; the NQNO, on the other hand, was identified in both Q(i) and Q(o) pockets in the inhibitor complex. The two inhibitors occupied different portions of the Q(i) pocket and competed with substrate for binding. In the Q(o) pocket, the NQNO behaves similarly to stigmatellin, inducing an iron-sulfur protein conformational arrest. Extensive binding interactions and conformational adjustments of residues lining the Q(i) pocket provide a structural basis for the high affinity binding of antimycin A and for phenotypes of inhibitor resistance. A two-water-mediated ubiquinone protonation mechanism is proposed involving three Q(i) site residues His(201), Lys(227), and Asp(228).

About this Structure

1NTM is a Protein complex structure of sequences from Bos taurus with and as ligands. Active as Ubiquinol--cytochrome-c reductase, with EC number 1.10.2.2 Full crystallographic information is available from OCA.

Reference

Structural basis for the quinone reduction in the bc1 complex: a comparative analysis of crystal structures of mitochondrial cytochrome bc1 with bound substrate and inhibitors at the Qi site., Gao X, Wen X, Esser L, Quinn B, Yu L, Yu CA, Xia D, Biochemistry. 2003 Aug 5;42(30):9067-80. PMID:12885240

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