This title appears in the Scientific Report : 2003 

Characterisation of subunit II and its oligomer from spinach chloroplast ATP synthase
Poetsch, A.
Rexroth, S. / Heberle, J. / Link, T. A. / Dencher, N. A. / Seelert, H.
Biologische Strukturforschung; IBI-2
Biochimica et biophysica acta / Biomembranes, 1618 (2003) S. 59 - 66
Amsterdam Elsevier 2003
59 - 66
Journal Article
BBA - Biomembranes 1618
Please use the identifier: in citations.
Proton ATP synthases carry out energy conversion in mitochondria, chloroplasts, and bacteria. A key element of the membrane integral motor CFO in chloroplasts is the oligomer of subunit III: it converts the energy of a transmembrane electrochemical proton gradient into rotational movement. To enlighten prominent features of the structure-function relationship of subunit III from spinach chloroplasts, new isolation methods were established to obtain highly pure monomeric and oligomeric subunit III in milligram quantities. By Fourier-transform infrared (FTIR) and CD spectroscopy, the predominantly a-helical secondary structure of subunit III was demonstrated. For monomeric subunit III, a conformational change was observed when diluting the SDS-solubilized protein. Under the same conditions the conformation of the oligomer III did not change. A mass of 8003 Da for the monomeric subunit III was determined by MALDI mass spectrometry (MALDI-MS), showing that no posttranslational modifications occurred. By ionisation during MALDI-MS, the noncovalent homooligomer III14 disaggregated into its III monomers. (C) 2003 Elsevier B.V All rights reserved.