1x13
From Proteopedia
(New page: 200px<br /><applet load="1x13" size="450" color="white" frame="true" align="right" spinBox="true" caption="1x13, resolution 1.90Å" /> '''Crystal structure of...) |
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| - | [[Image:1x13.gif|left|200px]]<br /><applet load="1x13" size=" | + | [[Image:1x13.gif|left|200px]]<br /><applet load="1x13" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1x13, resolution 1.90Å" /> | caption="1x13, resolution 1.90Å" /> | ||
'''Crystal structure of E. coli transhydrogenase domain I'''<br /> | '''Crystal structure of E. coli transhydrogenase domain I'''<br /> | ||
==Overview== | ==Overview== | ||
| - | The dimeric integral membrane protein nicotinamide nucleotide | + | The dimeric integral membrane protein nicotinamide nucleotide transhydrogenase is required for cellular regeneration of NADPH in mitochondria and prokaryotes, for detoxification and biosynthesis purposes. Under physiological conditions, transhydrogenase couples the reversible reduction of NADP+ by NADH to an inward proton translocation across the membrane. Here, we present crystal structures of the NAD(H)-binding domain I of transhydrogenase from Escherichia coli, in the absence as well as in the presence of oxidized and reduced substrate. The structures were determined at 1.9-2.0 A resolution. Overall, the structures are highly similar to the crystal structure of a previously published NAD(H)-binding domain, from Rhodospirillum rubrum transhydrogenase. However, this particular domain is unique, since it is covalently connected to the integral-membrane part of transhydrogenase. Comparative studies between the structures of the two species reveal extensively differing surface properties and point to the possible importance of a rigid peptide (PAPP) in the connecting linker for conformational coupling. Further, the kinetic analysis of a deletion mutant, from which the protruding beta-hairpin was removed, indicates that this structural element is important for catalytic activity, but not for domain I:domain III interaction or dimer formation. Taken together, these results have important implications for the enzyme mechanism of the large group of transhydrogenases, including mammalian enzymes, which contain a connecting linker between domains I and II. |
==About this Structure== | ==About this Structure== | ||
| - | 1X13 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Active as [http://en.wikipedia.org/wiki/NAD(P)(+)_transhydrogenase_(AB-specific) NAD(P)(+) transhydrogenase (AB-specific)], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.6.1.2 1.6.1.2] Full crystallographic information is available from [http:// | + | 1X13 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Active as [http://en.wikipedia.org/wiki/NAD(P)(+)_transhydrogenase_(AB-specific) NAD(P)(+) transhydrogenase (AB-specific)], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.6.1.2 1.6.1.2] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1X13 OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Johansson, T.]] | [[Category: Johansson, T.]] | ||
| - | [[Category: Karlsson, B | + | [[Category: Karlsson, B G.]] |
[[Category: Krengel, U.]] | [[Category: Krengel, U.]] | ||
[[Category: Okvist, M.]] | [[Category: Okvist, M.]] | ||
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[[Category: transhydrogenase]] | [[Category: transhydrogenase]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 15:50:04 2008'' |
Revision as of 13:50, 21 February 2008
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Crystal structure of E. coli transhydrogenase domain I
Overview
The dimeric integral membrane protein nicotinamide nucleotide transhydrogenase is required for cellular regeneration of NADPH in mitochondria and prokaryotes, for detoxification and biosynthesis purposes. Under physiological conditions, transhydrogenase couples the reversible reduction of NADP+ by NADH to an inward proton translocation across the membrane. Here, we present crystal structures of the NAD(H)-binding domain I of transhydrogenase from Escherichia coli, in the absence as well as in the presence of oxidized and reduced substrate. The structures were determined at 1.9-2.0 A resolution. Overall, the structures are highly similar to the crystal structure of a previously published NAD(H)-binding domain, from Rhodospirillum rubrum transhydrogenase. However, this particular domain is unique, since it is covalently connected to the integral-membrane part of transhydrogenase. Comparative studies between the structures of the two species reveal extensively differing surface properties and point to the possible importance of a rigid peptide (PAPP) in the connecting linker for conformational coupling. Further, the kinetic analysis of a deletion mutant, from which the protruding beta-hairpin was removed, indicates that this structural element is important for catalytic activity, but not for domain I:domain III interaction or dimer formation. Taken together, these results have important implications for the enzyme mechanism of the large group of transhydrogenases, including mammalian enzymes, which contain a connecting linker between domains I and II.
About this Structure
1X13 is a Single protein structure of sequence from Escherichia coli. Active as NAD(P)(+) transhydrogenase (AB-specific), with EC number 1.6.1.2 Full crystallographic information is available from OCA.
Reference
X-ray structure of domain I of the proton-pumping membrane protein transhydrogenase from Escherichia coli., Johansson T, Oswald C, Pedersen A, Tornroth S, Okvist M, Karlsson BG, Rydstrom J, Krengel U, J Mol Biol. 2005 Sep 16;352(2):299-312. PMID:16083909
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