X-ray-absorption-spectroscopy study of manganese-containing compounds and photosynthetic spinach chloroplasts

Technical Report · Fri May 01 00:00:00 EDT 1981

OSTI ID:6503375

Kirby, J A

The manganese sites in chloroplasts, long thought to be involved in photosynthetic oxygen evolution have been examined and partially characterized by x-ray Absorption Spectroscopy (XAS) using synchrotron radiation. The local environment about the manganese atoms is estimated from an analysis of the extended X-ray Absorption Fine Structure (EXAFS). Comparisons with and simulations of the manganese EXAFS for several reference compounds leads to a model in which the chloroplast manganese atoms are contained in a binuclear complex similar to di-u-oxo-tetrakis-(2,2'-bipyridine) dimanganese. It is suggested that the partner metal is another manganese. The bridging ligands are most probably oxygen. The remaining manganese ligands are carbon, oxygen, or nitrogen. A roughly linear correlation between the X-ray K edge onset energy and the coordination charge of a large number of manganese coordination complexes and compounds has been developed. Entry of the chloroplast manganese edge energy onto this correlation diagram establishes that the active pool of manganese is in an oxidation state greater than +2.

• Research Organization: Lawrence Berkeley Lab., CA (USA)
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 6503375
• Report Number(s): LBL-12705; ON: DE81024990
• Resource Relation: Other Information: Thesis
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
CHLOROPLASTS
MOLECULAR STRUCTURE
ABSORPTION SPECTROSCOPY
DATA ANALYSIS
EXPERIMENTAL DATA
FOURIER TRANSFORMATION
LIGANDS
MANGANESE
STRUCTURAL CHEMICAL ANALYSIS
X-RAY SPECTROSCOPY
CELL CONSTITUENTS
DATA
ELEMENTS
INFORMATION
INTEGRAL TRANSFORMATIONS
METALS
NUMERICAL DATA
SPECTROSCOPY
TRANSFORMATIONS
TRANSITION ELEMENTS
550200* - Biochemistry