We identified a @entity1432 -reactive substrate, @entity70030 ( @entity70031 ), to explore the contribution of the TM segments 6 and 12 of the @entity1 multidrug resistance @entity1262 ( @entity1262 ) during transport. @entity70031 is a trifunctional @entity15272 and stimulated the ATPase activity of @entity2569 -less @entity1262 about 7-fold. @entity462 -scanning mutagenesis of TM12 showed that the activity of mutant @entity70032 was inhibited by @entity70031 . @entity1262 mutants containing @entity70032 (TM12) and another @entity462 in TM6 were constructed and tested for cross-linking with @entity70031 . A @entity2915 was observed in @entity214 - @entity2975 gel electrophoresis for mutant L339C(TM6)/ @entity70032 (TM12). Cross-linking by @entity70031 also inhibited the ATPase activity of the mutant protein. Substrates such as @entity205 , @entity5713 , @entity3812 , or @entity1855 inhibited cross-linking by @entity70031 . In the presence of @entity855 at 37 degrees C, cross-linking of mutant L339C/ @entity70032 was decreased. In contrast, there was enhanced cross-linking of mutant @entity70033 (TM6)/ @entity70032 (TM12) in the presence of @entity855 . These results show that cross-linking must be within the drug-binding domain, that residues L339C(TM6)/ @entity70032 (TM12) must be at least 10 A apart, and that @entity855 hydrolysis promotes rotation of one or both TM helices.

Cross-linking of @entity1 multidrug resistance XXXX by the substrate, @entity70030 , is altered by @entity855 hydrolysis. Evidence for rotation of a transmembrane helix.

@entity1 :: ('9606', 'Species') :: ['human'] @entity70033 :: ('p|SUB|F|343|C', 'ProteinMutation') :: ['F343C'] @entity1262 :: ('5243', 'Gene') :: ['P-glycoprotein', 'P-gp'] @entity462 :: ('MESH:D003545', 'Chemical') :: ['cysteine', 'Cysteine'] @entity70031 :: ('CHEBI:271685', 'Chemical') :: ['TMEA'] @entity2569 :: ('CHEBI:17561', 'Chemical') :: ['Cys'] @entity1855 :: ('MESH:D014700', 'Chemical') :: ['verapamil'] @entity855 :: ('MESH:D000255', 'Chemical') :: ['ATP'] @entity1432 :: ('CHEBI:29256', 'Chemical') :: ['thiol'] @entity205 :: ('MESH:D016572', 'Chemical') :: ['cyclosporin A'] @entity2915 :: ('MESH:D006948', 'Disease') :: ['cross-linked product'] @entity2975 :: ('CHEBI:51135', 'Chemical') :: ['polyacrylamide'] @entity5713 :: ('MESH:D014747', 'Chemical') :: ['vinblastine'] @entity214 :: ('CHEBI:8984', 'Chemical') :: ['SDS'] @entity3812 :: ('MESH:D003078', 'Chemical') :: ['colchicine'] @entity70032 :: ('p|SUB|V|982|C', 'ProteinMutation') :: ['V982C'] @entity15272 :: ('MESH:C043592', 'Chemical') :: ['maleimide'] @entity70030 :: ('MESH:C434955', 'Chemical') :: ['Tris-(2-maleimidoethyl)amine']
@entity1262 :: (5243,Gene) :: ['P-glycoprotein']
