The coiled coil-helix-coiled coil-helix proteins may be redox proteins

A number of nuclear encoded proteins are imported in to the intermembrane space of mitochondria where they adopt a coiled coil-helix-coiled coil-helix (CHCH) fold. Two disulfide bonds formed by twin CX3C or CX9C motifs stabilize this fold. Some of these proteins are also characterized at their N-termini by the presence of two additional cysteine residues which can perform oxidoreductase or metallochaperone functions or both. This fold represents the most 'minimal' oxidoreductase domain described so far. (C) 2009 Federation of European Biochemical Societies. Published by Elsevier B. V. All rights reserved.