1g6h

<StructureSection load='1g6h' size='340' side='right' caption='[[1g6h]], [[Resolution|resolution]] 1.60&Aring;' scene=''>

<table><tr><td colspan='2'>[[1g6h]] is a 1 chain structure with sequence from [http://en.wikipedia.org/wiki/Methanocaldococcus_jannaschii Methanocaldococcus jannaschii]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1G6H OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1G6H FirstGlance]. <br>

</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=ADP:ADENOSINE-5-DIPHOSPHATE'>ADP</scene>, <scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene>, <scene name='pdbligand=MMC:METHYL+MERCURY+ION'>MMC</scene></td></tr>

<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1g6h FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1g6h OCA], [http://pdbe.org/1g6h PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=1g6h RCSB], [http://www.ebi.ac.uk/pdbsum/1g6h PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=1g6h ProSAT]</span></td></tr>

[[http://www.uniprot.org/uniprot/LIVG_METJA LIVG_METJA]] Probable component of a branched-chain amino-acid transport system.

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== Publication Abstract from PubMed ==

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.

 

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== References ==

[[Category: Hunt, J F]]

[[Category: Karpowich, N]]

[[Category: Martsinkevich, O]]

[[Category: Millen, L]]

[[Category: Thomas, P J]]

[[Category: Yuan, Y R]]

[[Category: Transport protein]]