Structural membrane proteomics- Respiratory chain complex I from thermophilic bacteria

Structural membrane proteomics- Respiratory chain complex I from thermophilic bacteria

Speaker: Guohong Peng

Affiliation: Max Planck Institut fur Biophysics, Frankfurt, Germany

Host: Metalloproteins and Bioenergetics Laboratory

Abstract:

Proteins from hyperthermophilic organisms are considered to be more stable and more rigid than their mesophilic counterparts. Therefore, the possibility of obtaining stable, homogeneous and crystallizable membrane protein complexes should be better with complexes from thermophilic organisms than with complexes from mesophilic ones. Thus, we have chosen to isolate stable membrane protein complexes from the hyperthermophilic eubacterium Aquifex aeolicus. A number of membrane proteins have been purified and characterized. All  protein complexes that we have purified to homogeneity in sufficient quantities, have yielded diffracting crystals.
Aquifex Complex I possesses highly stable and active properties. Single particle electron microscopy revealed many more details in its external arm, a pronounced invariant angle (90º) between the cytoplasmic arm and the membrane arm indicates a good preservation of the enzyme and a homogeneous preparation, which can improve crystallization attempts, and bring a promising solution for 3-D structural determination.