Amino acid sequence of the major component of Nostoc muscorum ferredoxin

The amino acid sequence of the major component of ferredoxin isolated from a blue-green alga, Nostoc muscorum, grown under N2 as the sole nitrogen source has been studied. The use of a combination of sequence analyzer, carboxypeptidases, and manual Edman degradations on tryptic and chymotryptic peptides of carboxymethylferredoxin has established the amino acid seuqence, which consists of 98 amino acid residues. Only four cysteine residues were present, located at positions 41, 46, 49, and 79. These residues must fulfil the minimum requirement in this ferredoxin for the chelation of two iron atoms, as postulated previously. The sequence is similar to those of Spirulina ferredoxins in having two extra residues at positions 10 and 14 compared with other chloroplast-type ferredoxins. Sequence comparison among blue-green algal ferredoxins suggests that Nostoc muscorum ferredoxin is more closely related to Spirulina ferredoxins than to Aphanothece major ferredoxin.

Amino acid sequence of the major component of Aphanothece sacrum ferredoxin

The amino acid sequence of the major ferredoxin component isolated from a blue-green alga, Aphanothece sacrum, has been fully determined. Chymotryptic and tryptic peptides of carboxymethyl-ferredoxin and chymotryptic peptides of oxidized ferredoxin were prepared and their sequences were analyzed...

Structure and function of chloroplast-type ferredoxins

Comparison of various chloroplast-type ferredoxin sequences, chemical and enzymic modifications, reconstitution experiments, and fluorescence measurement of chloroplast-type ferredoxins have led to the following conclusions. 1. Tyrosine, histidine, and tryptophan residues are not directly involved in the oxidation-reduction mechanism of ferredoxins. The four indispensible cysteine residues in spinach ferredoxin which constitutes a part of the iron-sulfur cluster are located at residues 39, 44. 47 and 77. Two out of six cysteine residues in Spirulina ferredoxin could be easily modified with vinylpyridine without the loss of reconstitutive ability i.e. the apoferredoxin could be converted to the holoform by the addition of iron and sulfide. 2. Spinach ferredoxin was digested with carboxypeptidase A and the terminal alanine could be removed without loss of the spectral properties of native ferredoxin. However, the removal of the terminal three residues gave rise to the loss of reconstitutive ability. 3. The amino groups of spinach ferredoxin were modified by acetic anhydride and four residues were acetylated. The acetylated preparation of ferredoxin had an unique spectrum. Upon the addition of high concentration of ions the spectrum of this derivative resembled the spectrum of native ferredoxin. Acetylferredoxin did not combine with ferredoxin-NADP reductase, but upon the addition of moderate concentrations of cations, it did bind to this enzyme.

Acetyl-coenzyme-A carboxylase from rat liver. Subunit structure and proteolytic modification

The subunit structure of rat liver acetyl-coenzyme-A carboxylase has been studied by polyacrylamide gel electrophoresis in the presence of dodecylsulfate. A number of individual preparations of the enzyme purified by the same procedures exhibited three different types of electrophoretic patterns as follows: first, a single slow-moving protein bands (Mr 230000); secondly, two adjacent fast-moving protein band (M4 124000 and 118 000); finally, all three protein bands. With the use of the [14C]biotin-labelled enzyme, the biotinyl prosthetic group was shown to be associated with the polypeptide of 230000 Mr as well as with that of 124000 Mr, but not with the polypeptide of 118000 Mr. Studies were next made with the labelled enzyme to examine the possibility that the two light polypeptides might have been formed by proteolytic modification of the heavy polypeptide during the procedures used for the purification of the enzyme. Treatment of the enzyme with trypsin or chymotrypsin resulted in cleavage of the heavy polypeptide into two nonidentical polypeptides with molecular weights of approximately 120000. Incubation of the enzyme with proteases derived from rat liver converted the heavy polypeptide into lighter polypeptides of 80000-130000 Mr. Acetyl-CoA carboxylase isolated from crude rat liver extracts by means of immunoprecipitation with specific antibody invariably showed only the heavy polypeptide. The biotin content of the enzyme was found to be 1 mol per 237000 g protein. These results indicate that rat liver acetyl-CoA carboxylase, unlike bacterial and plant biotin enzymes, has only one kind of subunit, which has a molecular weight of 230000 and contains one molecular of biotin. Thus, the mammalian enzyme exhibits a highly integrated subunit structure.

A minor component of ferredoxin from Aphanothece sacrum cells

About 20% of the total extractable ferredoxin from a blue-green alga, Aphanothece sacrum, was separated as a minor component on a DEAE-cellulose column during the preparation of the major component of the cells. It was always found in cells collected in three different seasons. The chemical properties of the minor component was different from those of the major one. The enzymatic activity and spectral properties were those of typical chloroplast-type ferredoxins. The significance of isozymes in ferredoxin is discussed.

Evolutionary information involved in primary structures of chloroplast-type ferredoxins

The complete amino acid sequence of a chloroplast-type ferredoxin from a fresh water prokaryote, Aphanothece sacrum, was determined. The sequence consisted of 96 amino acid residues and was homologous to those of ferredoxins of higher plants. Comparison of eight ferredoxins, including one from a green alga and three from blue-green algae, suggested that the sequences of algal ferredoxins were as different from one another as from those of higher plants. The relationship between the numbers of differences in amino acids and the period since separation from a common ancestor was not linear, even after correction for multiple substitution at an amino acid site in the sequence. It is very likely that the ferredoxins of angiosperms evolved rather rapidly and that those of algae, and particularly blue-green algae evolved rather slowly in the evolutionary scale. Several possible mechanisms of evolution of plants are discussed.

Changes of cheek pressure during swallowing following expansion of the maxillary dental arch in repaired cleft palates

Cheek pressure during swallowing was measured on six operated complete cleft lip and palate cases (4-8 years of age) before and after expansion of buccal segments of maxillary arch. As control, seven non-cleft subjects with acceptable occlusion of the same age level were used. Before expansion, the pressures in the cleft cases were much higher than the controls. Immediately after expansion, increase in pressure was observed in cases which received rapid expansion. However, a few months after expansion, most cases showed a decrease in pressure. This is explained as being due to the adaptation of the perioral musculature to the expanded dental arch and/or the disappearance of hyperactivity of the perioral musculature during swallowing.

Ischemic heart disease and hyperlipidemia

Studies on lipid and lipoprotein abnormalities which are associable with ischemic heart disease were presented. None of the subjects studied for this report had clinical signs or symptoms characteristic to "familial or sporadic" hyperlipoproteinemia. Only few showed gross abnormalities in lipid chemistries which are compatible with these clinical entities. Lipid abnormalities characteristic to the majority of ischemic heart patients were modest to moderate increase of serum total and free cholesterol and triglyceride; either independent increase or combined increase of these lipid fractions. Determination of free cholesterol may favor to detect such minute abnormality in modest hyperlipidemia as seen in ischemic heart patients. As expressed by our lipoprotein PAG electrophoresis pattern, B and Bp pattern (Fig. 1) seemed to be important lipoprotein abnormalities because of high incidence of ischemic heart disease (60 to 65%). Another feature of these hyperbeta lipoproteinemic state without (B pattern) or with (Bp pattern) moderate prebeta lipoprotein is highly suggestive of premature onset of ischemic heart suggestive premature onset of ischemic heart disease in the subjects with these lipoprotein patterns. Pb battern (hyperpre-beta lipoproteinemic state) was the next, because of frequent occurrence of this pattern (approx. 30%) among the cardiovascular patients and relatively high incidence (approx. 40%) of ischemic heart disease. PB pattern (combine hyperpre-beta and hyperbeta lipoproteinemic state) occurred rarely but incidence of ischemic heart disease in the subject with this pattern was high (approx. 40%). Midband lipoprotein which is one of the unique lipoprotein species detected by PAG electrophoresis may possibly reflect disordered lipoprotein metabolism. However, its association with ischemic heart disease seemed highly unlikely. However, further studies on this and other unusual lipoproteins detectable with PAG electrophoresis seems productive. Extensive studies on cine coronary angiographically established subjects (well characterized study subjects) with this new method in addition to the others would be highly productive to obtain more reliable conclusion on this subject, and hence, to obtain more effective guide line for early identification or for prevention of coronary atherosclerosis.

Study of an intravenous fat tolerance test with Intralipid. II. The relation between K2 and PHLA with special reference to clinical data in human subjects

The relation between K2 and PHLA was studied in human subjects with special reference to clinical data determined by routine laboratory and physical examinations. The results obtained by Multiple Regression Analysis indicated that those factors which may contribute to K2 variation were fasting triglyceride level and age. There was an inverse partial correlation between K2 and fasting triglyceride level and between K2 and age. The first and second principal components calculated by Principal Component Analysis indicated that K2 is closely related to obesity and hyperlipidemia, especially hypertriglyceridemia, while PHLA related to albumin. These two components also suggested that K2 fibes different clinical information from that obtained by PHLA measurement. There was no partial correlation between K2 and PHLA. The various lipoprotein paper electrophoretic patterns, type IIa, type IIb, type IV and normal patterns, were clearly characterized by such factors as K2, plasma triglyceride and degree of obesity which has high coefficients in the first principal component.