3bci

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==Overview==
==Overview==
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Bacterial Dsb proteins catalyse the in vivo formation of disulfide bonds, a critical step in the stability and activity of many proteins. Most studies on Dsb proteins have focused on Gram-negative bacteria and thus the process of oxidative folding in Gram-positive bacteria is poorly understood. To help elucidate this process in Gram-positive bacteria, DsbA from Staphylococcus aureus (SaDsbA) has been focused on. Here, the expression, purification, crystallization and preliminary diffraction analysis of SaDsbA are reported. SaDsbA crystals diffract to a resolution limit of 2.1 A and belong to the hexagonal space group P6(5) or P6(1), with unit-cell parameters a = b = 72.1, c = 92.1 A and one molecule in the asymmetric unit (64% solvent content).
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In Gram-negative bacteria, the introduction of disulfide bonds into folding proteins occurs in the periplasm and is catalyzed by donation of an energetically unstable disulfide from DsbA, which is subsequently re-oxidized through interaction with DsbB. Gram-positive bacteria lack a classic periplasm but nonetheless encode Dsb-like proteins. Staphylococcus aureus encodes just one Dsb protein, a DsbA, and no DsbB. Here we report the crystal structure of S. aureus DsbA (SaDsbA), which incorporates a thioredoxin fold with an inserted helical domain, like its Escherichia coli counterpart EcDsbA, but it lacks the characteristic hydrophobic patch and has a truncated binding groove near the active site. These findings suggest that SaDsbA has a different substrate specificity than EcDsbA. Thermodynamic studies indicate that the oxidized and reduced forms of SaDsbA are energetically equivalent, in contrast to the energetically unstable disulfide form of EcDsbA. Further, the partial complementation of EcDsbA by SaDsbA is independent of EcDsbB and biochemical assays show that SaDsbA does not interact with EcDsbB. The identical stabilities of oxidized and reduced SaDsbA may facilitate direct re-oxidation of the protein by extracellular oxidants, without the need for DsbB.
==About this Structure==
==About this Structure==
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==Reference==
==Reference==
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Expression and crystallization of DsbA from Staphylococcus aureus., Heras B, Kurz M, Jarrott R, Byriel KA, Jones A, Thony-Meyer L, Martin JL, Acta Crystallogr Sect F Struct Biol Cryst Commun. 2007 Nov 1;63(Pt, 11):953-6. Epub 2007 Oct 24. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=18007049 18007049]
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Staphylococcus aureus DsbA Does Not Have a Destabilizing Disulfide: A NEW PARADIGM FOR BACTERIAL OXIDATIVE FOLDING., Heras B, Kurz M, Jarrott R, Shouldice SR, Frei P, Robin G, Cemazar M, Thony-Meyer L, Glockshuber R, Martin JL, J Biol Chem. 2008 Feb 15;283(7):4261-71. Epub 2007 Dec 12. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=18077463 18077463]
[[Category: Single protein]]
[[Category: Single protein]]
[[Category: Staphylococcus aureus]]
[[Category: Staphylococcus aureus]]
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[[Category: thiol-disulfide oxidoreductase]]
[[Category: thiol-disulfide oxidoreductase]]
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''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri Mar 14 09:43:53 2008''

Revision as of 07:43, 14 March 2008


3bci, resolution 1.810Å

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Crystal Structure of Staphylococcus aureus DsbA

Overview

In Gram-negative bacteria, the introduction of disulfide bonds into folding proteins occurs in the periplasm and is catalyzed by donation of an energetically unstable disulfide from DsbA, which is subsequently re-oxidized through interaction with DsbB. Gram-positive bacteria lack a classic periplasm but nonetheless encode Dsb-like proteins. Staphylococcus aureus encodes just one Dsb protein, a DsbA, and no DsbB. Here we report the crystal structure of S. aureus DsbA (SaDsbA), which incorporates a thioredoxin fold with an inserted helical domain, like its Escherichia coli counterpart EcDsbA, but it lacks the characteristic hydrophobic patch and has a truncated binding groove near the active site. These findings suggest that SaDsbA has a different substrate specificity than EcDsbA. Thermodynamic studies indicate that the oxidized and reduced forms of SaDsbA are energetically equivalent, in contrast to the energetically unstable disulfide form of EcDsbA. Further, the partial complementation of EcDsbA by SaDsbA is independent of EcDsbB and biochemical assays show that SaDsbA does not interact with EcDsbB. The identical stabilities of oxidized and reduced SaDsbA may facilitate direct re-oxidation of the protein by extracellular oxidants, without the need for DsbB.

About this Structure

3BCI is a Single protein structure of sequence from Staphylococcus aureus. Full crystallographic information is available from OCA.

Reference

Staphylococcus aureus DsbA Does Not Have a Destabilizing Disulfide: A NEW PARADIGM FOR BACTERIAL OXIDATIVE FOLDING., Heras B, Kurz M, Jarrott R, Shouldice SR, Frei P, Robin G, Cemazar M, Thony-Meyer L, Glockshuber R, Martin JL, J Biol Chem. 2008 Feb 15;283(7):4261-71. Epub 2007 Dec 12. PMID:18077463

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