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The amino acid sequence of the protamine isolated from mature sperm nuclei of the ram (Ovis aries) has been established from automated sequence analysis of the S-carboxymethylated protamine. Ram and bull protamines differ only by two point changes and the deletion in bull protamine of the tripeptide Cys39-Arg-Arg41. In mammalian protamines the central region (residues 13–36) consisting mainly of arginine clusters appears to be conserved whereas the N-terminal and C-terminal regions are more variable. [ABSTRACT FROM AUTHOR]

Vitellin was identified and purified from submature oocytes of Perinereis cultrifera by concanavalin-A— Sepharose and Ultrogel AcA 34 column chromatography. The yolk protein was defined as a glycolipoprotein with a relative molecular mass of 380000. Upon dissociation by sodium dodecyl sulphate, vitellin was shown to release five polypeptide subunits which ranged in relative molecular mass from 98000-16000. The purified vitellin was further characterized by amino acid analysis and its lipid and carbohydrate contents. The molecule contained about 5% carbohydrate and 16% lipid. Antiserum prepared against vitellin was shown to react with a component from the coelomic fluid of maturing females. Thus, it was suggested that in nereid annelids, considered phylogenetically and morphologically primitive, oocyte differentiation might depend upon the incorporation of a vitellogenin as in insects and many oviparous vertebrates. [ABSTRACT FROM AUTHOR]

The complete amino acid sequence (125 residues) of sea urchin histone H2A has been established by structural studies of peptides derived from tryptic and chymotryptic cleavage of the maleylated protein and from thermolysin cleavage of the intact protein. By comparison with calf homologous histone, the basic amino-terminal and carboxy-terminal parts of the protein show 11 substitutions and 4 deletions. The remainder of the sequence, mostly hydrophobic, is almost completely unchanged. [ABSTRACT FROM AUTHOR]

Inter-α-trypsin inhibitor (ITI) is a tight complex of three different proteins: bikunin and two heavy chains H1 and H2. In order to demonstrate that the three chains are covalently linked by a chondroitin sulphate chain as previously proposed [Enghild. J. J., Salvesen, G., Hefta. S. A., Thoger sen. I. B., Rutherford. S. and Pizzo. S. V. (1991) J. Biol. Chem. 266, 747-751], ITI was extensively digested with thermolysin and the glycosaminoglycan-containing fragment was isolated from the digest by ion-exchange chromatography. Its peptide structural determination and mass spectrometry analysis both provide evidence that the different peptide chains constituting ltl are associated by the new cross-link described as the protein-glycosaminoglycan-protein cross-link. [ABSTRACT FROM AUTHOR]

A 14-kDa protein was identified as a major component of mature oocytes of the leech Theromyzon tessulatum. This protein was, like vitellin, detected in the content of yolk granules and was purified by gel-permeation and ion-exchange chromatography. The yolk protein corresponded to an iron-binding protein which exists in a monomeric unglycosylated form and had no similarities to vitellin. However, a strong resemblance between this protein and sipunculid hemerythrin, a non-heme iron-binding protein, was observed on the basis of its characteristics including molecular mass, iron content, ultraviolet/visible spectrum, amino acid composition and N-terminal sequence. These similarities with hemerythrin and the accumulation of the protein in the oocyte justify the name ovohemerythrin given to the molecule. A coelomic-fluid protein immunologically related to ovohemerythrin was detected in vitellogenic animals. The protein was purified with the chromatographic procedure used to isolate ovohemerythrin from oocytes and was found to be similar to the oocyte protein. This circulating ovohemerythrin was present in large amounts in the coelomic fluid while gametogenesis is in progress, i.e. after the third and last blood meal of the animal (stage 3), except at the time of oocyte enlargement when its concentration decreases dramatically. However, in contrast to vitellogenin, which is detected specifically in the coelomic fluid of leeches at stage 3, circulating ovohemerythrin is also observed after the first (stage 1) and second (stage 2) blood meal. This observation suggests a more complex function for ovohemerythrin than being merely a yolk nutrient for the embryo. [ABSTRACT FROM AUTHOR]

The amino acid sequence of the protein HMb, a protein of 93 residues (Mr 10757) which represents the major acid-soluble component of the Methanosarcina barren nucleoprotein complex, has been established from automated sequence analysis of the protein and from structural data provided by peptides derived from cleavage of the protein at aspartic acid, arginine and methionine residues. The protein HMb is mainly characterized by a high amount of charged residues (15% of acidic residues and 26.8% of basic residues) which are distributed all along the polypeptide chain. The amino acid sequence of the protein HMb is not homologous to any eubacterial, archaebacterial or eukaryotic chromosomal proteins known up to now. [ABSTRACT FROM AUTHOR]

The amino acid sequences of the two variants (H1a 121 residues and H1b 119 residues) of the sperm-specific histone H1 from the polychaete annelid Platynereis dumerilii have been completely established. Comparison of the sequences of these two variants shows one deletion of two residues in histone H1b and 22 substitents, of which most occur in the globular domain. The two variants differ highly in a sequence of nine residues adjacent to the conservative phenylalanine residue of histone H1 (64–72 in H1a, 62–70 in H1b) which makes H I a less hydrophobic than H1b. The small molecular size of Platynereis H1a and H1b is a unique feature among the histones H1 of which the size ranges between 189 residues (chicken erythrocyte H5) and 248 residues (sea urchin sperm H1). H1a and H1b have short N- and C-terminal basic domains but the size of the globular domain (&assymp;80 residues) is similar to that of other H1s. In the globular region the variant H1a exhibits a close relationship with somatic or sperm H1s whereas the variant H1b is more related to H5 histones. [ABSTRACT FROM AUTHOR]

The complete amino acid sequence (121 residues) of histone H2B from gonads of the starfish Asterias rubens has been established form structural data obtained essentially from large fragments generated by cleavage of histone H2B at aspartyl residues and by limited hydrolysis of th dimer H2A-H2B with mouse submaxillary gland protease. No real sequence homology can be found between the amino-terminal sequence (residues 1-21) of starfish and calf H2B. One non-conservative substitution(serine-32 in calf → lysine-28 in starfish) leads to the presence of a cluster of eight basic residues (sequence 23-30) and to the disappearance of a potential site of phosphorylation. A particular structural feature of starfish histone H2B is the presence of N-dimethylproline at its aminoterminal end. By comparison with N-terminal acetylation, which is commonly found in histones, N-terminal methylation is rarely observed. At the present time the functional significance of the N-terminal methylation as well as that of the proline-rich nature of the amino-terminal sequence of the starfish histone H2B remain to be defined. [ABSTRACT FROM AUTHOR]

The DNA-binding HU-type proteins from several species of Rhizobiaceae including Rhizobium meliloti, two strains of Rhizobium leguminosarum with highly different phenotypic characters and Agrobacterium tumefaciens, were characterized and their amino acid sequences were determined. HU-type proteins isolated form R. leguminosarum L18 and A. tumefaciens are identical and show slight differences with the R. meliloti HU-type protein. On the other hand the R. leguminosarum L53 HU-type protein is quite different from the proteins cited above; several amino acid substitutions encountered in this protein result bacteria in the phylogeny determined by numerical taxonomy. [ABSTRACT FROM AUTHOR]

Human inter-α-inhibitor (IαI) is a plasma serine-proteinase inhibitor. It consists of three polypeptide chains covalently linked by a glycosaminoglycan : a light one named bikunin, carrying the antiproteinase activity and two heavy chains H1 and H2. The amino acid sequences of these heavy chains are highly similar; however when IαI is digested by neutrophil proteinases, their proteolytic susceptibility strongly differs [Balduyck, M., Piva, F., Mizon, C., Maes, P., Malki, N., Gressier, B., Michalski, C. & Mizon, J. (1993) Human leucocyte elastase (HLE) preferentially cleaves the heavy chain H2 of inter-α-trypsin inhibitor (ITI), Biol. Chem. Hoppe-Seyler 374, 895-901]. We mapped the disulphide topology of the IαI heavy chains in order to investigate whether or not disulphide bonds might be responsible for their differential susceptibility to proteolysis. Using amino acid sequencing and mass spectrometry analysis, we demonstrate that the H1 heavy chain contains one free thiol group and two disulphide bridges of which one links two largely spaced cysteine residues (Cys239 and Cys511). Thus H1 is clearly different from H2 which contains two disulphide bonds between closely located cysteine residues. However, using immunoprint analysis, we show that, when IαI is subjected to a limited digestion by Staphylococcus aureus V-8 proteinase, the two polypeptide chains are similarly susceptible to proteolysis. This enzyme preferentially cleaves the IαI heavy chains from their N-terminal extremity. These results are consistent with the circular dichroism (CD) analysis, suggesting that the conformation of the polypeptide backbone of H1 is not very different from that of H2, with calculated α-helicities of 24 % and 28 %, respectively. The CD measurements reveal that the aromatic amino acids of H1 and H2 are in a different asymmetrical environment. Inside the IαI molecule, the heavy chains are linked to the glycosaminoglycan chain via... [ABSTRACT FROM AUTHOR]

The complete amino acid sequence (123 residues) of histone H2A from erythrocytes of the marine worm Sipunculus nudus, has been established from data provided by automated sequence analysis of large fragments generated by V8 staphylococcal protease digestion of histone H2A and by limited hydrolysis of the protein with α-chymotrypsin and from structural studies of tryptic peptides of the protein. By comparison with calf homologous histone, the sipunculid histone H2A shows 6 deletions and 13 substitutions. Six of the substitutions are non-conservative. Most of the evolutionary changes are mainly observed in tile basic amino-terminal and carboxy-terminal regions of the molecule, which are the primary DNA-binding sites. Few conservative point changes are observed in the central region (residues 18–118) which interacts strongly with histone H2B to form the dimer H2A-H2B. 60% of the H2A molecules were found phosphorylated on the amino-terminal residue, N-acetyl-serine. The high content of phosphorylated histone H2A in the sipunculid erythrocyte chromatin could probably be related to smaller repeat length (177 ± 5 base pairs) of nucleosomal DNA and to nuclear inactivation and chromatin condensation. [ABSTRACT FROM AUTHOR]