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  • The presence of disulfide bonds reveals an evolutionarily conserved mechanism involved in mitochondrial protein translocase assembly.

The presence of disulfide bonds reveals an evolutionarily conserved mechanism involved in mitochondrial protein translocase assembly.

Scientific reports (2016-06-07)
Lidia Wrobel, Anna M Sokol, Magdalena Chojnacka, Agnieszka Chacinska
ABSTRACT

Disulfide bond formation is crucial for the biogenesis and structure of many proteins that are localized in the intermembrane space of mitochondria. The importance of disulfide bond formation within mitochondrial proteins was extended beyond soluble intermembrane space proteins. Tim22, a membrane protein and core component of the mitochondrial translocase TIM22, forms an intramolecular disulfide bond in yeast. Tim22 belongs to the Tim17/Tim22/Tim23 family of protein translocases. Here, we present evidence of the high evolutionary conservation of disulfide bond formation in Tim17 and Tim22 among fungi and metazoa. Topological models are proposed that include the location of disulfide bonds relative to the predicted transmembrane regions. Yeast and human Tim22 variants that are not oxidized do not properly integrate into the membrane complex. Moreover, the lack of Tim17 oxidation disrupts the TIM23 translocase complex. This underlines the importance of disulfide bond formation for mature translocase assembly through membrane stabilization of weak transmembrane domains.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Anti-β-Actin antibody, Mouse monoclonal, clone AC-15, purified from hybridoma cell culture
Sigma-Aldrich
Anti-Myc Tag Antibody, clone 4A6, clone 4A6, Upstate®, from mouse
Sigma-Aldrich
Methoxypolyethylene glycol maleimide, ≥90% (NMR), 5,000