A further study on the dietary-regulated biosynthesis of high-sulphur wool proteins

When the diet of sheep is supplemented by the infusion of sulphur-containing amino acids or casein into the abomasum, the newly synthesized wool shows characteristic changes in its amino acid composition, with significant increases in cystine, proline and serine and decreases in aspartic acid and phenylalanine. This modification seems to be due entirely to an alteration in the overall composition of the high-sulphur proteins and to an increase in their proportion in the fibre. These variations are not the result of a change in the composition of individual proteins, but are due to alterations in their relative proportions and to the initiation of the synthesis of `new' proteins, many of which are extremely rich in cystine. It is suggested that the heterogeneity of the high-sulphur proteins may be due, in part, to similar changes in composition caused by natural variations in the nutrition of sheep.     

The preparation and properties of a group of proteins from the high-sulphur fraction of wool

A method is reported for the preparation of a group of three proteins from the S-carboxymethylated high-sulphur fraction of wool. These proteins have been partially characterized by their tryptic peptides. All have similar structural features and show an interesting homology within the group and some similarities of sequence with a different group of wool high-sulphur proteins. The evidence for the sequence of some of the peptides is given in a supplementary paper that has been deposited as Supplementary Publication 50008 at the National Lending Library for Science and Technology, Boston Spa, Yorks. LS23 7BQ, U.K., from whom copies can be obtained on the terms indicated in Biochem. J. (1972) 126, 5.     

Studies on the high-sulphur proteins of reduced Merino wool. Amino acid sequence of protein SCMKB-IIIB4

The complete amino acid sequence of protein SCMKB-IIIB4 is presented. It is closely related to the sequence of protein SCMKB-IIIB3 (Haylett, Swart & Parris, 1971) differing in only four positions. The peptic and thermolysin peptides of protein SCMKB-IIIB4 were analysed by the dansyl-Edman method (Gray, 1967) and by tritium-labelling of C-terminal residues (Matsuo, Fujimoto & Tatsuno, 1966). This protein is the third member of a group of high-sulphur wool proteins with molecular weight of about 11400. It consists of 98 residues and has acetylalanine and carboxymethylcysteine as N- and C-terminal residues respectively.     

Studies on the high-sulphur proteins of reduced Merino wool. Amino acid sequence of protein SCMBK-IIIB3

The complete amino acid sequence of wool protein SCMKB-IIIB3 was determined. The peptides used for the sequence work were obtained by peptic and thermolysin digestions and were fractionated by chromatography on DEAE-cellulose, paper chromatography and electrophoresis. The peptides were analysed by dansyl-Edman degradation, mass spectrometry and tritium-labelling of C-terminal residues. The protein consists of 98 residues and has acetylalanine as N-terminal residue and carboxymethylcysteine as C-terminus. It is homologous with protein SCMKB-IIIB2 (Haylett & Swart, 1969). A salient feature of the sequence of protein SCMKB-IIIB3 is three consecutive cysteine residues.     

Studies on the high-sulphur proteins of reduced Merino wool. Amino acid sequence of protein SCMKB-IIIA3

The complete amino acid sequences of wool protein SCMKB-IIIA3 (131 residues) and a minor component SCMKB-IIIA3A (130 residues) have been determined. The proteins are mutually homologous and have free threonine as the N-terminal residue and carboxymethylcysteine as the C-terminus. The peptides used for the sequence work were obtained by trypsin, thermolysin, pepsin and chymotrypsin digestions and were fractionated by chromatography on DEAE-cellulose, gel filtration on Sephadex G-25 and G-50, paper chromatography and electrophoresis. The Edman degradation method (employing both the Beckman Sequencer and a non-automatic procedure) was used to obtain the sequences of the peptides.     

Mammalian keratin gene families: organisation of genes coding for the B2 high-sulphur proteins of sheep wool.

We have isolated two genomic clones containing three B2 high-sulphur keratin genes from a sheep genomic library constructed in Charon 4A. These genes do not contain intervening sequences. Two genes, encoding the B2A and B2D proteins are closely linked in the genome, being separated by 1.9 kb, and are transcribed in the same direction. Although there is extensive sequence conservation in the 5' non-coding and coding regions, the 3' non-coding regions diverge both in length and sequence. Within the 5' non-coding region adjacent to the initiating AUG there is a highly conserved 18 bp sequence which is also present in another gene coding for a member of a different, unrelated high-sulphur keratin family. In the B2A-B2D intergene region, tightly linked to the B2D gene, there is a putative, divergently transcribed gene.     

The amino acid sequence of protein SCMK-B2A from the high-sulphur fraction of wool keratin

1. The amino acid sequence of protein SCMK-B2A, a reduced and S-carboxymethylated protein from the high-sulphur fraction of wool, has been determined. 2. This protein of 171 amino acid residues displays both a high degree of internal homology and extensive external homology with other members of the SCMK-B2 group of proteins. 3. Evidence is presented which suggests that the SCMK-B2 group of proteins are produced by separate non-allelic genes.     

The amino acid sequence of protein SCMK-B2C from the high-sulphur fraction of wool keratin

1. The amino acid sequence of a protein from the reduced and carboxymethylated high-sulphur fraction of wool has been determined. 2. The sequence of this S-carboxymethylkerateine (SCMK-B2C) of 151 amino acid residues displays much internal homology and an unusual residue distribution. Thus a ten-residue sequence occurs four times near the N-terminus and five times near the C-terminus with few changes. These regions contain much of the molecule's half-cystine, whereas between them there is a region of 19 residues that are mainly small and devoid of cystine and proline. 3. Certain models of the wool fibre based on its mechanical and physical properties propose a matrix of small compact globular units linked together to form beaded chains. The unusual distribution of the component residues of protein SCMK-B2C suggests structures in the wool-fibre matrix compatible with certain features of the proposed models.     

Evidence of homology in a high-sulphur protein fraction (SCMK-B2) of wool and hair α-keratins

Fractions corresponding to the S-carboxymethylated high-sulphur protein component SCMK-B2 isolated by Gillespie (1963) from Merino wool were prepared from five different wool samples and also from bovine hair. The six fractions showed great similarities in amino acid composition, and also gave very similar peptide ;maps' after tryptic and chymotryptic digestion. Some of the peptides were isolated from the different samples, and evidence is given that suggests that a sequence of at least 21 amino acids is common to all the fraction SCMK-B2 preparations. Further, all the fractions derived from the wool samples have the same acetylated heptapeptide for the N-terminal sequence, but one extra residue may be present in this N-terminal sequence in the protein from bovine hair. The general significance of these findings is discussed.     

The biosynthesis of neutrophil and eosinophil granule proteins

Composition of azurophil and specific granules from human polymorphonuclear neutrophils and granules from eosinophils is presented. Biosynthesis of the granule proteins is discussed in detail with particular emphasis on neutrophil myeloperoxidase (MPO) and eosinophil cationic protein (ECP).