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| | {{STRUCTURE_1g6h| PDB=1g6h | SCENE= }} | | {{STRUCTURE_1g6h| PDB=1g6h | SCENE= }} |
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| - | '''CRYSTAL STRUCTURE OF THE ADP CONFORMATION OF MJ1267, AN ATP-BINDING CASSETTE OF AN ABC TRANSPORTER'''
| + | ===CRYSTAL STRUCTURE OF THE ADP CONFORMATION OF MJ1267, AN ATP-BINDING CASSETTE OF AN ABC TRANSPORTER=== |
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| - | ==Overview==
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| - | BACKGROUND: ATP binding cassette (ABC) transporters are ubiquitously distributed transmembrane solute pumps that play a causative role in numerous diseases. Previous structures have defined the fold of the ABC and established the flexibility of its alpha-helical subdomain. But the nature of the mechanical changes that occur at each step of the chemical ATPase cycle have not been defined. RESULTS: Crystal structures were determined of the MJ1267 ABC from Methanococcus jannaschii in Mg-ADP-bound and nucleotide-free forms. Comparison of these structures reveals an induced-fit effect at the active site likely to be a consequence of nucleotide binding. In the Mg-ADP-bound structure, the loop following the Walker B moves toward the Walker A (P-loop) coupled to backbone conformational changes in the intervening "H-loop", which contains an invariant histidine. These changes affect the region believed to mediate intercassette interaction in the ABC transporter complex. Comparison of the Mg-ADP-bound structure of MJ1267 to the ATP-bound structure of HisP suggests that an outward rotation of the alpha-helical subdomain is coupled to the loss of a molecular contact between the gamma-phosphate of ATP and an invariant glutamine in a segment connecting this subdomain to the core of the cassette. CONCLUSIONS: The induced-fit effect and rotation of the alpha-helical subdomain may play a role in controlling the nucleotide-dependent change in cassette-cassette interaction affinity believed to represent the power-stroke of ABC transporters. Outward rotation of the alpha-helical subdomain also likely facilitates Mg-ADP release after hydrolysis. The MJ1267 structures therefore define features of the nucleotide-dependent conformational changes that drive transmembrane transport in ABC transporters.
| + | The line below this paragraph, {{ABSTRACT_PUBMED_11470432}}, adds the Publication Abstract to the page |
| | + | (as it appears on PubMed at http://www.pubmed.gov), where 11470432 is the PubMed ID number. |
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| | + | {{ABSTRACT_PUBMED_11470432}} |
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| | ==About this Structure== | | ==About this Structure== |
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| | [[Category: Abc specific-beta-strand domain alpha-helix domain]] | | [[Category: Abc specific-beta-strand domain alpha-helix domain]] |
| | [[Category: Beta-core domain]] | | [[Category: Beta-core domain]] |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 17:11:55 2008'' | + | |
| | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Tue Jul 1 04:43:44 2008'' |
Revision as of 01:43, 1 July 2008
Template:STRUCTURE 1g6h
CRYSTAL STRUCTURE OF THE ADP CONFORMATION OF MJ1267, AN ATP-BINDING CASSETTE OF AN ABC TRANSPORTER
Template:ABSTRACT PUBMED 11470432
About this Structure
1G6H is a Single protein structure of sequence from Methanocaldococcus jannaschii. Full crystallographic information is available from OCA.
Reference
Crystal structures of the MJ1267 ATP binding cassette reveal an induced-fit effect at the ATPase active site of an ABC transporter., Karpowich N, Martsinkevich O, Millen L, Yuan YR, Dai PL, MacVey K, Thomas PJ, Hunt JF, Structure. 2001 Jul 3;9(7):571-86. PMID:11470432
Page seeded by OCA on Tue Jul 1 04:43:44 2008
