TY - JOUR

T1 - A structural investigation of complex I and I + III2 supercomplex from Zea mays at 11-13 Å resolution

T2 - Assignment of the carbonic anhydrase domain and evidence for structural heterogeneity within complex I

AU - Peters, Katrin

AU - Dudkina, Natalya V.

AU - Jänsch, Lothar

AU - Braun, Hans Peter

AU - Boekema, Egbert J.

N1 - Funding information: We thank Dr. Roman Kou?il and Dr. Wilko Keegstra for their help with the processing and modelling of supercomplex structures and Dr. Gert Oostergetel for invaluable help with electron microscopy. We also like to thank Dr. M. Radermacher for providing Yarrowia lipolytica complex I images. Dagmar Lewejohann is thanked for expert technical assistance. Research of our laboratories is supported by the Deutsche Forschungsgemeinschaft (grant Br 1829-7/3).

PY - 2007/11/4

Y1 - 2007/11/4

N2 - The projection structures of complex I and the I + III2 supercomplex from the C4 plant Zea mays were determined by electron microscopy and single particle image analysis to a resolution of up to 11 Å. Maize complex I has a typical L-shape. Additionally, it has a large hydrophilic extra-domain attached to the centre of the membrane arm on its matrix-exposed side, which previously was described for Arabidopsis and which was reported to include carbonic anhydrase subunits. A comparison with the X-ray structure of homotrimeric γ-carbonic anhydrase from the archaebacterium Methanosarcina thermophila indicates that this domain is also composed of a trimer. Mass spectrometry analyses allowed to identify two different carbonic anhydrase isoforms, suggesting that the γ-carbonic anhydrase domain of maize complex I most likely is a heterotrimer. Statistical analysis indicates that the maize complex I structure is heterogeneous: a less-abundant "type II" particle has a 15 Å shorter membrane arm and an additional small protrusion on the intermembrane-side of the membrane arm if compared to the more abundant "type I" particle. The I + III2 supercomplex was found to be a rigid structure which did not break down into subcomplexes at the interface between the hydrophilic and the hydrophobic arms of complex I. The complex I moiety of the supercomplex appears to be only of "type I". This would mean that the "type II" particles are not involved in the supercomplex formation and, hence, could have a different physiological role.

AB - The projection structures of complex I and the I + III2 supercomplex from the C4 plant Zea mays were determined by electron microscopy and single particle image analysis to a resolution of up to 11 Å. Maize complex I has a typical L-shape. Additionally, it has a large hydrophilic extra-domain attached to the centre of the membrane arm on its matrix-exposed side, which previously was described for Arabidopsis and which was reported to include carbonic anhydrase subunits. A comparison with the X-ray structure of homotrimeric γ-carbonic anhydrase from the archaebacterium Methanosarcina thermophila indicates that this domain is also composed of a trimer. Mass spectrometry analyses allowed to identify two different carbonic anhydrase isoforms, suggesting that the γ-carbonic anhydrase domain of maize complex I most likely is a heterotrimer. Statistical analysis indicates that the maize complex I structure is heterogeneous: a less-abundant "type II" particle has a 15 Å shorter membrane arm and an additional small protrusion on the intermembrane-side of the membrane arm if compared to the more abundant "type I" particle. The I + III2 supercomplex was found to be a rigid structure which did not break down into subcomplexes at the interface between the hydrophilic and the hydrophobic arms of complex I. The complex I moiety of the supercomplex appears to be only of "type I". This would mean that the "type II" particles are not involved in the supercomplex formation and, hence, could have a different physiological role.

KW - Carbonic anhydrase

KW - Complex I

KW - Cytochrome c reductase

KW - Electron microscopy

KW - Supercomplex

KW - Zea mays

UR - http://www.scopus.com/inward/record.url?scp=37549064026&partnerID=8YFLogxK

U2 - 10.1016/j.bbabio.2007.10.012

DO - 10.1016/j.bbabio.2007.10.012

M3 - Article

C2 - 18047828

AN - SCOPUS:37549064026

VL - 1777

SP - 84

EP - 93

JO - Biochimica et Biophysica Acta - Bioenergetics

JF - Biochimica et Biophysica Acta - Bioenergetics

SN - 0005-2728

IS - 1

ER -