Probing the proton channels in subunit N of Complex I from Escherichia coli through intra-subunit cross-linking.

ABSTRACT: Respiratory Complex I appears to have 4 sites for proton translocation, which are coupled to the oxidation of NADH and reduction of coenzyme Q. The proton pathways are thought to be made of offset half-channels that connect to the membrane surfaces, and are connected by a horizontal path through the center of the membrane. In this study of the enzyme from Escherichia coli, subunit N, containing one of the sites, was targeted. Pairs of cysteine residues were introduced into neighboring α-helices along the proposed proton pathways. In an effort to constrain conformational changes that might occur during proton translocation, we attempted to form disulfide bonds or methanethiosulfonate bridges between two engineered cysteine residues. Cysteine modification was inferred by the inability of PEG

SUBMITTER: Tursun A 

PROVIDER: S-EPMC5079763 | biostudies-literature | 2016 Dec

REPOSITORIES: biostudies-literature