J. A. M. Ramshaw

A phylogeny of higher plants based on the amino acid sequences of cytochrome c and its biological implications

Higher plant phylogenetic trees were constructed from the amino acid sequences of cytochrome c from fifteen plants using the ‘ancestral sequence’ and ‘flexible numerical’ methods. The validity of these methods is discussed and the results obtained are compared with existing phylogenies based mainly on morphological characters.

Higher plant plastocyanin

Abstract Plastocyanin has been purified from six species of higher plants of wide taxonomic distribution. The molecular properties have been shown to be similar in all cases. Higher plant plastocyanin has a molecular weight of about 10 500 and contains 1 copper atom per molecule.

The amino acid sequence of plastocyanin from spinach. (Spinacia oleracea L.).

The amino acid sequence of spinach (Spinacia oleracea L.) plastocyanin was determined. It consists of a single polypeptide chain of 99 residues and has a sequence molecular weight of 10415. The sequence was determined by using a Beckman 890C automatic sequencer and by the dansyl--phenyl isothiocyanate analysis of peptides obtained by the enzymic digestion of purified CNBr fragments. Overlap through the two methionine residues was not shown. Sedimentation equilibrium in the ultracentrifuge gave a molecular weight for spinach plastocyanin of about 9000, in contrast with the value of 21000 reported previously by Katoh et al. (1962).

Isolation and purification of cytochrome c from some species of higher plants.

Abstract Cytochrome c was isolated and purified from dark-grown seedlings of mung bean, sunflower, sesame, castor oil and buckwheat. The major steps of the method employed were adsorption on Amberlite CG-50, concentration on Sephadex CM-50, molecular sieve chromatography on Bio-gel P-30 and Sephadex G-50, and ion-exchange chromatography on CM-52 Cellulose. Unlike previous methods for the purification of cytochrome c this method did not involve the use of organic solvents during the initial extraction, or fractional precipitation of the protein with ammonium sulphate. The Ampholine iso-electric focusing technique was also investigated as a possible method in the purification of cytochrome c from plant sources. The final yield of purified cytochrome c from the various species was in the range 0·2–0·45 mg/kg dry seeds.

Cytochrome cs from Rhodymenia palmata and Porphyra umbilicalis and the amino acid sequences of their N-terminal regions

Abstract Basic c -type cytochromes homologous with plant and animal mitochondrial cytochrome c have been isolated and purified from Rhodymenia palmata and Porphyra umbilicalis . The N -terminal regions have been analysed using a Beckman 890C automatic sequencer. When compared to animal cytochrome c , the Rhodymenia cytochrome c has an unblocked N -terminal tail of 10 amino acids, whereas Porphyra has an unblocked N -terminal tail of only a single amino acid.

Structure-function relationships in plant cytochrome c

Abstract Structure-function relationships in plant cytochrome c are discussed in the light of Dickersons horse heart and bonito ferricytochromes c model, in conjunction with the complete amino acid sequences of 14 plant cytochromes c .

The amino acid sequence of rape (Brassica Napus L) cytochrome c

The amino acid sequence of rape (Brassica Napus L) cytochrome c was determined using 1 mumole of protein. Analysis of chymotryptic and tryptic peptides by the dansyl-Edman method showed that the molecule consisted of 111 residues and was homologous with other mitochondrial plant cytochromes c. The amino acid sequence was found to be identical with that previously reported for the cytochrome c from cauliflower (Brassica oleracea L).

The amino acid sequence of cytochrome c from niger-seed, Guizotia abyssinica

Abstract The amino acid sequence of cytochrome c from niger-seed has been determined by sequence analysis of chymotryptic and tryptic peptides using the dansyl-phenylisothiocyanate method and by qualitative analysis of peptide composition by the dansyl method. Although the spectral ratios indicated the protein was not completely pure, no indication of impurity was found during the sequence analysis and no peptides in addition to those given here were obtained. In certain cases the alignment of peptides was by homology with other cytochromes c . Four residues in the proposed sequence, alanine-1, cysteine-25, histidine-26 and lysine-61 were identified only from peptide compositions. The amino-terminus of the protein is acetylated. The sequence contains two residues of ϵ- N -trimethyllysine.

Phylogenetic implications of the amino acid sequence of cytochrome c from Enteromorpha intestinalis

Abstract The amino acid sequence of Epiteromorpha cytochrome c has been added to an affinity tree relating the cytochrome c sequences of animals, plants, fungi, protozoans and one bacterium, cytochrome c 2 from Rhodospirillum . The Enteromorpha sequence lies on the line of descent of the higher plant sequences; it is not closely related to the cytochrome c of the photosynthetic protozoan, Euglena . The distribution of e- N -trimethyllysine in cytochrome c is discussed.

The amino acid sequence of plastocyanin from Lactuca sativa (lettuce)

Abstract The amino acid sequence of plastocyanin from lettuce ( Lactuca sativa L.) was determined by using a Beckman 890C automatic sequencer and by dansyl-phenylisothiocyanate analysis of peptides obtained by enzymic digestion of purified CNBr fragments. The protein consists of a single polypeptide chain of 99 residues, and shows close homology with other higher plant plastocyanins. The data are discussed in relation to the possible residues involved in the binding of copper in plastocyanin.