Voelcker Academy

Research Symposium 2012


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Abhinav Suri

An Analysis of Protein Subunits in Complex I of Mitochondria

Abhinav Suri

Mentor(s): Rasika Vartak, Yidong Bai, PhD

NADH:ubiquinone oxidoreductase, or complex I, is the largest and least understood component of the mitochondrial oxidative phosphorylation system. It oxidizes NADH, which is generated through the Krebs cycle in the mitochondrial matrix, and uses the two electrons to reduce ubiquinone to ubiquinol. Ubiquinol is re-oxidized by the cytochrome bc1 complex and transfers electrons to reduce molecular oxygen to water at complex IV. The redox energy released during this process is used to transfer protons from the mitochondrial matrix to the periplasmic space that generates proton-motive force across the inner mitochondrial membrane at complex I, III, and IV. Complex V uses this proton-motive force to produce ATP from ADP and inorganic phosphate. Progress has been made in recent years in understanding its subunit composition, its assembly, the interaction among complex I and other respiratory components, and its role in oxidative stress and apoptosis. Complex I is a membrane bound assembly consisting of multiple parts:

  • 45 polypeptide subunits (38 coded by nuclear DNA, 7 coded by mtDNA).
  • combined mass of 1 Mda
  • These subunits are bound together into subcomplex assemblies and eventually into a complex via various assembly proteins, which also maintain the stability of the complex.
  • The lab focuses on the structure of complex I, its cellular functions, and discusses the implication of complex I dysfunction in various human diseases.