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Ref ID : 4540

Francisco Galvan, Antonio J. Marquez, and Emilio Fernandez; Physicochemical Properties of Ferredoxin from Chlamydomonas reinhardii. Z.Naturforsch. 40c:373-378, 1985

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Ferredoxin from Chlamydomonas reinhardii has been purified to electrophoretic homogeneity by an easy and fast procedure with a high yield (25-30 mg/250 g wet weight of cells). An average molecular weight of 11800 was calculated from sedimentation coefficient (1.70 S) and Stokes radius (1.75 nm) data, sodium dodecyl sulfate-electrophoresis, and amino acid composition. Absorption spectrum showed maxima at 276, 330, 420 and 460 nm in the oxidized form, with an absorption ratio (A420/A276) of 0.54 and an extinction coefficient of 8.38 mM(-1) cm(-1) at 420 nm. Reduced ferredoxin showed a single peak at 276 nm with shoulders at 284, 310, 390, 469 and 537 nm and at liquid helium temperatures gave EPR signals at g=1.877, 1.951 and 2.045. The protein has an isoelectric point of 3.30, and one (2Fe-2S)-cluster per molecule with a midpoint potential, at pH 7.5, of -410 mV (n=1). The molecule of C. reinhardii ferredoxin consists of 95-99 amino acid residues which includes the full complement of amino acids, being alanine the most abundant.