1x14: Difference between revisions

Revision as of 16:50, 21 February 2008

Crystal structure of E. coli transhydrogenase domain I with bound NAD

OverviewOverview

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 StructureAbout this Structure

1X14 is a Single protein structure of sequence from Escherichia coli with as ligand. Active as NAD(P)(+) transhydrogenase (AB-specific), with EC number 1.6.1.2 Full crystallographic information is available from OCA.

ReferenceReference

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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OCA

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-[[Image:1x14.gif|left|200px]]<br /><applet load="1x14" size="450" color="white" frame="true" align="right" spinBox="true"
+[[Image:1x14.gif|left|200px]]<br /><applet load="1x14" size="350" color="white" frame="true" align="right" spinBox="true"
 caption="1x14, resolution 1.94&Aring;" />
 '''Crystal structure of E. coli transhydrogenase domain I with bound NAD'''<br />
 ==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.
+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==
-X14 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli] with NAD as [http://en.wikipedia.org/wiki/ligand ligand]. 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://ispc.weizmann.ac.il/oca-bin/ocashort?id=1X14 OCA].
+X14 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli] with <scene name='pdbligand=NAD:'>NAD</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. 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=1X14 OCA].
 ==Reference==
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 [[Category: Single protein]]
 [[Category: Johansson, T.]]
-[[Category: Karlsson, B.G.]]
+[[Category: Karlsson, B G.]]
 [[Category: Krengel, U.]]
 [[Category: Okvist, M.]]
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 [[Category: transhydrogenase]]
-''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Wed Nov 21 05:47:07 2007''
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