The soluble @entity577 monooxygenase (sMMO) complex from @entity34170 ) catalyses @entity26 - and @entity1110 -dependent oxygenation of @entity577 , @entity23137 , and other substrates. Whole-complex sMMO oxygenase activity requires all three sMMO components: the hydroxylase, the reductase, and protein B. Also, in the presence of @entity273 , the hydroxylase alone catalyzes substrate oxygenation via the @entity2625 shunt reaction. We investigated the effect of @entity6115 cross-linking on hydroxylase activity to probe the role of a gross conformational change that occurs in the hydroxylase upon binding of the other protein components. The cross-linker inhibited hydroxylase activity in the whole complex, but this effect was due to covalent modification of @entity2229 groups rather than cross-linking. Covalent modification of @entity369 side-chains on the hydroxylase had a similar effect, but, most remarkably, neither form of modification affected the activity of the hydroxylase via the @entity2625 shunt reaction. It was shown that covalent modification of positively charged groups on the hydroxylase, which occurred at multiple sites, interfered with its physical and functional interactions with protein B and with the passage of electrons from the reductase. These results indicate that protein B and the reductase of the sMMO complex interact via positively charged groups on the surface of the hydroxylase to induce a conformational change that is necessary for delivery of electrons into the active site of the hydroxylase. Modification of positively charged groups on protein B had no effect on its function, consistent with the hypothesis that positively charged groups on the hydroxylase interact with negative charges on protein B. Thus, we have discovered a means of specifically inactivating the interactions between the sMMO complex while preserving the catalytic activity of the hydroxylase active site which provides a new method of studying intercomponent interactions within sMMO.

Positively charged amino acids are essential for electron transfer and protein-protein interactions in the soluble XXXX monooxygenase complex from @entity34170 ).

@entity2229 :: ('CHEBI:32877', 'Chemical') :: ['primary amine'] @entity26 :: ('MESH:D010100', 'Chemical') :: ['oxygen'] @entity23137 :: ('MESH:C013658', 'Chemical') :: ['propene'] @entity2625 :: ('CHEBI:44785', 'Chemical') :: ['peroxide'] @entity6115 :: ('CHEBI:32952', 'Chemical') :: ['amine'] @entity1110 :: ('MESH:D009249', 'Chemical') :: ['NAD(P)H'] @entity273 :: ('MESH:D006861', 'Chemical') :: ['hydrogen peroxide'] @entity577 :: ('MESH:D008697', 'Chemical') :: ['methane'] @entity34170 :: ('243233', 'Species') :: ['Methylococcus capsulatus (Bath'] @entity369 :: ('CHEBI:29016', 'Chemical') :: ['arginine']
@entity577 :: (MESH:D008697,Chemical) :: ['methane']
