A Diatom Light-Harvesting Pigment-Protein Complex
- 1 October 1984
- journal article
- Published by Oxford University Press (OUP) in Plant Physiology
- Vol. 76 (2), 483-489
- https://doi.org/10.1104/pp.76.2.483
Abstract
A light-harvesting pigment-protein complex was isolated from the diatom Phaeodactylum tricornutum using the zwitterionic detergent CHAPS (3-[3-cholamidopropyl)dimethylammonio]-1-propanesulfonate). Detergent-solubilized membranes were fractionated by sucrose density gradient centrifugation into three components. The medium density fraction contained chlorophyll a, chlorophyll c, and fucoxanthin. This fraction was purified by DEAE-ion exchange chromatography, and contained chlorophyll a, chlorophyll c, and fucoxanthin in a molar ratio of 2.4:1.0:4.8. Fluorescence emission and excitation spectra of the isolated complex demonstrated that light energy absorbed by chlorophyll c and fucoxanthin was coupled to chlorophyll a fluorescence. Upon denaturation, the apoprotein yielded a polypeptide doublet at 17.5 to 18.0 kilodaltons which accounted for 30 to 40% of the toal membrane protein. These findings indicate that this pigment-protein complex is a major component of the diatom photosynthetic lammellae. The quantitative amino acid composition of the apoprotein was very similar to those reported for other membrane-bound pigment-protein complexes. Based on the protein to chlorophyll a ratio of 7700 grams protein per mole chlorophyll a for the complex, each apoprotein molecule contains, to the nearest integer, two chlorophyll a, one chlorophyll c, and five fucoxanthin molecules. Polyclonal antibodies raised against the 17.5 to 18.0 kilodaltons apoprotein showed a monospecific reaction with only the 17.5 to 18.0 protein zone from denatured P. tricornutum membranes as well as to the nondenatured pigment-protein complex. It appears that this complex is common to other diatom species.Keywords
This publication has 14 references indexed in Scilit:
- P700 Chlorophyll a-ProteinPlant Physiology, 1983
- Light-harvesting systems of brown algae and diatoms. Isolation and characterization of chlorophyllBiochimica et Biophysica Acta (BBA) - Bioenergetics, 1981
- The P-700-chlorophyl a-protein complex and two major light-harvesting complexes of Acrocarpia paniculata and other brown seaweedsBiochimica et Biophysica Acta (BBA) - Bioenergetics, 1980
- Electrophoretic transfer of proteins from polyacrylamide gels to nitrocellulose sheets: procedure and some applications.Proceedings of the National Academy of Sciences of the United States of America, 1979
- A manganese-copper-pigment-protein complex isolated from the photosystem II of Phaeodactylum tricornutumArchives of Biochemistry and Biophysics, 1977
- Peridinin-Chlorophyll a Proteins of the Dinoflagellate Amphidinium carterae (Plymouth 450)Plant Physiology, 1976
- The Light-harvesting Chlorophyll a/b-Protein Complex of Chlamydomonas reinhardiiPlant Physiology, 1976
- High-resolution preparative SDS-polyacrylamide gel electrophoresis: Fluorescent visualization and electrophoretic elution-concentration of protein bandsAnalytical Biochemistry, 1975
- Cleavage of Structural Proteins during the Assembly of the Head of Bacteriophage T4Nature, 1970
- STUDIES OF MARINE PLANKTONIC DIATOMS: I. CYCLOTELLA NANA HUSTEDT, AND DETONULA CONFERVACEA (CLEVE) GRAN.Canadian Journal of Microbiology, 1962