Structure of the manganese complex of photosystem II upon removal of the 33-kilodalton extrinsic protein: an X-ray absorption spectroscopy study

Journal Article · Tue Sep 22 04:00:00 EDT 1987 · Biochemistry; (United States)

DOI:https://doi.org/10.1021/bi00393a004· OSTI ID:5559863

Cole, J L; Yachandra, V K; McDermott, A E; Guiles, R D; Britt, R D; Dexheimer, S L; Sauer, K; Klein, M P

The structure of the Mn complex of photosystem II (PSII) was studied by X-ray absorption spectroscopy. Oxygen-evolving spinach PSII membranes containing 4-5 Mn/PSII were treated with 0.8 M CaCl/sub 2/ to extract the 33-, 24-, and 16-kilodalton (kDa) extrinsic membrane proteins. Mn was not released by this treatment, but subsequent incubation at low Cl/sup -/ concentration generated preparations containing 2 Mn/PSII. The Mn X-ray absorption K-edge spectrum of the CaCl/sub 2/-washed preparation containing 4 Mn/PSII is very similar to the spectrum of native PSII, indicating that the oxidation states and ligand symmetry of the Mn complex in these preparations are not significantly different. The Mn extended X-ray absorption find structure (EXAFS) of CaCl/sub 2/-washed PSII fits to a Mn neighbor at approx. 2.75 A and two shells of N or O at approx. 1.78 and approx. 1.92 A. The results demonstrate that the structure of the Mn complex is largely unaffected by removal of 33-, 24-, and 16-kDa extrinsic proteins, and thus these proteins do not provide ligands to Mn. The Mn K-edge spectrum of the CaCl/sub 2/-washed sample containing 2 Mn/PSII has a dramatically altered shape, and the edge infection point is shifted to lower energy. The position of the edge is consistent with a Mn oxidation state of +3. The Mn EXAFS of this preparation is also quite different and cannot be simulated by using the parameters for the native Mn complex. Thus the structure of the Mn complex is disrupted upon depletion of half of the Mn.

• Research Organization: Lawrence Berkeley Lab., CA
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 5559863
• Journal Information: Biochemistry; (United States), Journal Name: Biochemistry; (United States) Vol. 26:19; ISSN BICHA
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
140505 -- Solar Energy Conversion-- Photochemical
Photobiological
& Thermochemical Conversion-- (1980-)
550601* -- Medicine-- Unsealed Radionuclides in Diagnostics
62 RADIOLOGY AND NUCLEAR MEDICINE
ABSORPTION SPECTROSCOPY
ACCELERATORS
COMPLEXES
CYCLIC ACCELERATORS
ELECTROPHORESIS
FOOD
MANGANESE COMPLEXES
MEMBRANES
PHOTOSYNTHETIC MEMBRANES
PHOTOSYNTHETIC REACTION CENTERS
PLANTS
SPECTRA
SPECTROSCOPY
SPINACH
SYNCHROTRONS
TRANSITION ELEMENT COMPLEXES
VEGETABLES
X-RAY SPECTRA
X-RAY SPECTROSCOPY