Respiratory supercomplexes enhance electron transport by decreasing cytochrome c diffusion distance

• Respiratory chains are crucial for cellular energy conversion and consist of multi-subunit complexes that can assemble into supercomplexes. These structures have been intensively characterized in various organisms, but their physiological roles remain unclear. Here, we elucidate their function by leveraging a high-resolution structural model of yeast respiratory supercomplexes that allowed us to inhibit supercomplex formation by mutation of key residues in the interaction interface. Analyses of a mutant defective in supercomplex formation, which still contains fully functional individual complexes, show that the lack of supercomplex assembly delays the diffusion of cytochromec between the separated complexes, thus reducing electron transfer efficiency. Consequently, competitive cellular fitness is severely reduced in the absence of supercomplex formation and can be restored by overexpression of cytochromec. In sum, our results establish how respiratory supercomplexes increase the efficiency of cellular energy conversion, thereby providing an evolutionary advantage for aerobic organisms.

Subject headings

NATURVETENSKAP  -- Biologi -- Biokemi och molekylärbiologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences -- Biochemistry and Molecular Biology (hsv//eng)

MEDICIN OCH HÄLSOVETENSKAP  -- Medicinska och farmaceutiska grundvetenskaper -- Cell- och molekylärbiologi (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Basic Medicine -- Cell and Molecular Biology (hsv//eng)

NATURVETENSKAP  -- Biologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences (hsv//eng)

Keyword

bioenergetics

competitive fitness

cryo-EM

mitochondria

respiratory

chain supercomplexes

complex-i

kinetic evidence

bc(1) complex

b synthesis

chain

yeast

assembly/stability

visualization

mitochondria

relevance

Biochemistry & Molecular Biology

Cell Biology

bioenergetics

Publication and Content Type

ref (subject category)

art (subject category)