TY - JOUR

T1 - Megacomplex organization of the oxidative phosphorylation system by structural analysis of respiratory supercomplexes from potato

AU - Bultema, Jelle B.

AU - Braun, Hans Peter

AU - Boekema, Egbert J.

AU - Kouřil, Roman

PY - 2008/11/13

Y1 - 2008/11/13

N2 - The individual protein complexes of the oxidative phosphorylation system (OXPHOS complexes I to V) specifically interact and form defined supramolecular structures, the so-called "respiratory supercomplexes". Some supercomplexes appear to associate into larger structures, or megacomplexes, such as a string of dimeric ATP synthase (complex V2). A row-like organization of OXPHOS complexes I, III and IV into respiratory strings has also been proposed. These transient strings cannot be purified after detergent solubilization. Hence the shape and composition of the respiratory string was approached by an extensive structural characterization of all its possible building blocks, which are the supercomplexes. About 400,000 molecular projections of supercomplexes from potato mitochondria were processed by single particle electron microscopy. We obtained two-dimensional projection maps of at least five different supercomplexes, including the supercomplex I + III2, III2 + IV1, V2, I + III2 + IV1 and I2 + III2 in different types of position. From these maps the relative position of the individual complexes in the largest unit, the I2 + III2 + IV2 supercomplex, could be determined in a coherent way. The maps also show that the I + III2 + IV1 supercomplex, or respirasome, differs from its counterpart in bovine mitochondria. The new structural features allow us to propose a consistent model of the respiratory string, composed of repeating I2 + III2 + IV2 units, which is in agreement with dimensions observed in former freeze-fracture electron microscopy data.

AB - The individual protein complexes of the oxidative phosphorylation system (OXPHOS complexes I to V) specifically interact and form defined supramolecular structures, the so-called "respiratory supercomplexes". Some supercomplexes appear to associate into larger structures, or megacomplexes, such as a string of dimeric ATP synthase (complex V2). A row-like organization of OXPHOS complexes I, III and IV into respiratory strings has also been proposed. These transient strings cannot be purified after detergent solubilization. Hence the shape and composition of the respiratory string was approached by an extensive structural characterization of all its possible building blocks, which are the supercomplexes. About 400,000 molecular projections of supercomplexes from potato mitochondria were processed by single particle electron microscopy. We obtained two-dimensional projection maps of at least five different supercomplexes, including the supercomplex I + III2, III2 + IV1, V2, I + III2 + IV1 and I2 + III2 in different types of position. From these maps the relative position of the individual complexes in the largest unit, the I2 + III2 + IV2 supercomplex, could be determined in a coherent way. The maps also show that the I + III2 + IV1 supercomplex, or respirasome, differs from its counterpart in bovine mitochondria. The new structural features allow us to propose a consistent model of the respiratory string, composed of repeating I2 + III2 + IV2 units, which is in agreement with dimensions observed in former freeze-fracture electron microscopy data.

KW - Electron microscopy

KW - Respiratory string

KW - Respiratory supercomplex

KW - Single particle analysis

UR - http://www.scopus.com/inward/record.url?scp=57649211340&partnerID=8YFLogxK

U2 - 10.1016/j.bbabio.2008.10.010

DO - 10.1016/j.bbabio.2008.10.010

M3 - Article

C2 - 19059196

AN - SCOPUS:57649211340

VL - 1787

SP - 60

EP - 67

JO - Biochimica et Biophysica Acta - Bioenergetics

JF - Biochimica et Biophysica Acta - Bioenergetics

SN - 0005-2728

IS - 1

ER -