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| | {{STRUCTURE_2r5o| PDB=2r5o | SCENE= }} | | {{STRUCTURE_2r5o| PDB=2r5o | SCENE= }} |
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| - | '''Crystal structure of the C-terminal domain of wzt'''
| + | ===Crystal structure of the C-terminal domain of wzt=== |
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| - | ==Overview==
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| - | ATP-binding-cassette (ABC) transporters are responsible for the export of a wide variety of cell-surface glycoconjugates in both Gram-positive and Gram-negative bacteria. These include the O-antigenic polysaccharide (O-PS) portion of lipopolysaccharide, a crucial virulence determinant in Gram-negative pathogens. O-PSs are synthesized by one of two fundamentally different pathways. Escherichia coli O serotypes O8 and O9a provide the prototype systems for studying O-PS export via ABC transporters. The transporter is composed of the transmembrane component Wzm and the nucleotide-binding component Wzt. Although the N-terminal domain of Wzt is a conventional ABC protein, the C-terminal domain of Wzt (C-Wzt) is a unique structural element that determines the specificity of the transporter for either the O8 or O9a O-PS. We show here that the two domains of Wzt can function when expressed as separate polypeptides; both are essential for export. In vitro, C-Wzt binds its cognate O-PS by recognizing a residue located at the nonreducing end of the polymer. The crystal structure of C-Wzt(O9a) is reported here and reveals a beta sandwich with an immunoglobulin-like topology that contains the O-PS-binding pocket. Substrate interactions with nucleotide-binding domains have been demonstrated in an ABC exporter previously. However, to our knowledge substrate binding by a discrete, cytoplasmic accessory domain in an extended nucleotide-binding domain polypeptide has not previously been demonstrated. Elucidation of the substrate-recognition system involved in O-PS export provides insight into the mechanism that coordinates polymer biosynthesis, termination, and export.
| + | The line below this paragraph, {{ABSTRACT_PUBMED_18032609}}, adds the Publication Abstract to the page |
| | + | (as it appears on PubMed at http://www.pubmed.gov), where 18032609 is the PubMed ID number. |
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| | + | {{ABSTRACT_PUBMED_18032609}} |
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| | ==About this Structure== | | ==About this Structure== |
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| | [[Category: O antigen export]] | | [[Category: O antigen export]] |
| | [[Category: Transport protein]] | | [[Category: Transport protein]] |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun May 4 16:17:34 2008'' | + | |
| | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Mon Jul 28 11:59:47 2008'' |
Revision as of 08:59, 28 July 2008
Template:STRUCTURE 2r5o
Crystal structure of the C-terminal domain of wzt
Template:ABSTRACT PUBMED 18032609
About this Structure
2R5O is a Single protein structure of sequence from Escherichia coli. Full crystallographic information is available from OCA.
Reference
Substrate binding by a bacterial ABC transporter involved in polysaccharide export., Cuthbertson L, Kimber MS, Whitfield C, Proc Natl Acad Sci U S A. 2007 Dec 4;104(49):19529-34. Epub 2007 Nov 21. PMID:18032609
Page seeded by OCA on Mon Jul 28 11:59:47 2008
