A novel experiment has been used to show proximity relationships between sites on the surface of the cytochrome bd oxidase of Escherichia coli The artificial protease iron (S)-l-[p-(broinoacetamido)benzy]-EDTA (Fe-BABE) was conjugated to selected reactive cysteines placed in subunit I or subunit II, with the aim of identifying amino acid residues with in -12 angstroms of each site of attachment The protease was activated with hydrogen peroxide and ascorbate for a few seconds, and hydrolysis products were isolated and analyzed by N-terminal sequencing Among other results, we found that residue 39 of subunit II is near residue 255 of the subunit I in the putative quinone-binding domain (Q-loop) of the oxidase Since this technique is insensitive to the nature of the amino acid side chains, it should prove generally valuable in revealing spatial relationships both within and betweensubunits in complex proteins where high- resolution structural information is not available.
|Original language||English (US)|
|State||Published - 1997|
ASJC Scopus subject areas
- Molecular Biology