Format

Send to

Choose Destination
Structure. 1997 Dec 15;5(12):1613-25.

Biological identity and diversity in photosynthesis and respiration: structure of the lumen-side domain of the chloroplast Rieske protein.

Author information

1
Department of Biological Sciences, Purdue University, West Lafayette, IN 47907-1392, USA.

Abstract

BACKGROUND:

The cytochrome b6f complex functions in oxygenic photosynthesis as an integral membrane protein complex that mediates coupled electron transfer and proton translocation. The Rieske [2Fe-2S] protein subunit of the complex functions at the electropositive (p) membrane interface as the electron acceptor for plastoquinol and donor for the cytochrome f subunit, and may have a dynamic role in catalyzing electron and proton transfer at the membrane interface. There are significant structure/function similarities to the cytochrome bc1 complex of the respiratory chain.

RESULTS:

The 1.83 A crystal structure of a 139-residue C-terminal fragment of the Rieske [2Fe-2S] protein, derived from the cytochrome b6f complex of spinach chloroplasts, has been solved by multiwavelength anomalous diffraction. The structure of the fragment comprises two domains: a small 'cluster-binding' subdomain and a large subdomain. The [2Fe-2S] cluster-binding subdomains of the chloroplast and mitochondrial Rieske proteins are virtually identical, whereas the large subdomains are strikingly different despite a common folding topology. A structure-based sequence alignment of the b6f and bc1 groups of Rieske soluble domains is presented.

CONCLUSIONS:

The segregation of structural conservation and divergence in the cluster-binding and large subdomains of the Rieske protein correlates with the overall relatedness of the cytochrome b6f and bc1 complexes, in which redox domains in the aqueous p phase are dissimilar and those within the membrane are similar. Distinct sequences and surface charge distributions among Rieske large subdomains may provide a signature for interaction with the p-side oxidant protein and for the pH of the intraorganelle compartment.

PMID:
9438861
DOI:
10.1016/s0969-2126(97)00309-2
[Indexed for MEDLINE]
Free full text

Supplemental Content

Full text links

Icon for Elsevier Science
Loading ...
Support Center