title: Determination of double decker sandwich structured La-substituted chlorophyll a by EXAFS.
abstract: As a representative natural porphyrin derivative, it is interesting to know the chemical form of lanthanide in chlorophyll a. We select the natural fern dicranopteris dichotoma, the most lanthanide-concentrated plant known, to isolate the chlorophyll a for our study. It is found by EXAFS that lanthanum substitutes in the magnesium position in chlorophyll and coordinates with the porphyrin ring. The lanthanum is seen to have a similar coordination structure to a sandwich-type lanthanide complex, with the La surrounded by eight nitrogen atoms from two porphyrin rings with average La-N bond length of 2.65 A.
authors.affiliation: Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, China. taoy@alpha02.ihep.ac.cn
authors.forename: Y
authors.initials: Y
authors.lastname: Tao
authors.forename: G
authors.initials: G
authors.lastname: Zhao
authors.forename: J
authors.initials: J
authors.lastname: Yang
authors.forename: S
authors.initials: S
authors.lastname: Ikeda
authors.forename: J
authors.initials: J
authors.lastname: Jiang
authors.forename: T
authors.initials: T
authors.lastname: Hu
authors.forename: W
authors.initials: W
authors.lastname: Chen
authors.forename: Z
authors.initials: Z
authors.lastname: Wei
authors.forename: F
authors.initials: F
authors.lastname: Hong
mesh_terms: D002734:Chlorophyll / Q000737:chemistry*; D000077194:Chlorophyll A; D007811:Lanthanum / Q000737:chemistry*; D008274:Magnesium / Q000737:chemistry; D015394:Molecular Structure; D010944:Plants / Q000737:chemistry*; D013052:Spectrometry, X-Ray Emission / Q000379:methods
chemical_list: D002734:Chlorophyll; D007811:Lanthanum; D008274:Magnesium; D000077194:Chlorophyll A