Sequence differences between histones of procyclic Trypanosoma brucei brucei and higher eukaryotes

Four histones, a, b, c, d from procyclic Trypanosoma brucei brucei, which show similarities with the amino acid composition of the core histones H3, H2A, H2B and H4, were isolated and cleaved with Endoproteinase Glu-C. The fragments were separated by FPLC reversed phase chromatography and a subset of the fragments (a5, a9, b6, c8, d3, d9, d11) was subjected to sequence analysis. A 54-71% identity was found in the sequences of the fragment c8 and the C-terminal half of H2B and of three fragments of protein d covering the N-terminal half as well as the C-terminal region of H4. The amino acid sequence of the fragment a9 showed a 57 and 54% identity with H3 sequences of Saccharomyces cerevisiae and Xenopus laevis. Neither the a5 nor the b6 sequence could be aligned with histone sequences of other eukaryotes. The significant differences of 21-48% between the T.b. brucei histone sequences and those of calf thymus histones, which are more pronounced than the differences of Tetrahymena pyriformis and the higher eukaryote, resulted partially from replacements of amino acids with different properties and indicate specific patterns of histone-histone and/or histone-DNA contact sites in the nucleosome of T.b. brucei. These differences, together with the lack of a functional histone H1, may be sufficient to explain the lack of a salt-dependent formation of the nucleosome filament into the 30 nm fibre, which reflects alternative methods of organizing and processing the genetic information in the nucleus of the protozoan parasite and which may be of chemotherapeutic significance.

[Onset of disseminated Bloch-Sulzberger incontinentia pigmenti]

The case report of a 2-week-old girl suffering from incontinentia pigmenti (Bloch-Sulzberger Syndrome) with disseminated urticarial erythemas, papules and vesicles at the onset is presented. Histological examination showed eosinophilic spongiosis. The peripheral blood eosinophilia and the development of typical lesions led to the diagnosis of incontinentia pigmenti. Eosinophilic spongiosis and peripheral blood eosinophilia are important symptoms in the diagnosis of atypical incontinentia pigmenti.

Amino acid sequence of human plasma galactoglycoprotein: identity with the extracellular region of CD43 (sialophorin)

The amino acid sequence of galactoglycoprotein purified from human plasma was elucidated to 75% completeness by using chemical degradation of peptides and glycopeptides derived from digests of the protein with seven specific proteases. This sequence represents a polypeptide chain of approximately 220 amino acid residues including a high content of serine, threonine, alanine, and proline with one N-linked and multiple O-linked glycans. Comparison of peptide sequences from the native galactoglycoprotein and the deglycosylated derivative demonstrated the locations of 25 sites of O-glycosylation and three serine sites that are not glycosylated. The homogeneous N terminus was established as serine. C-terminal analysis revealed multiple C-terminal residues, suggesting that galactoglycoprotein molecules are of varying lengths. A search of a protein data base revealed that the galactoglycoprotein polypeptide is identical to the N-terminal (extracellular) polypeptide region of the blood-cell surface molecule CD43 (sialophorin, leukosialin). Further support of the relatedness of these molecules was obtained by immunoprecipitation of 125I-labeled galactoglycoprotein by monoclonal anti-CD43 antibodies. The composition and properties of the molecules together with the known structure of the gene encoding CD43 suggest that galactoprotein is derived by proteolytic cleavage from transmembrane "hexasaccharide CD43," known to be expressed on neutrophils, activated T lymphocytes, and platelets.

Biochemical properties of histone-like proteins of procyclic Trypanosoma brucei brucei

Four histone-like proteins a, b, c, d were extracted with 0.2 M H2SO4 from soluble nuclear chromatin of Trypanosoma brucei brucei procyclic culture forms and purified by FPLC reversed phase chromatography. The amino acid composition of these proteins and their electrophoretic mobilities in three different gel systems strongly indicated their core histone nature. Similarities were found between a, b, c and d with the core histones H3, H2A, H2B and H4 of higher eukaryotes, respectively. On the other hand, these proteins also showed differences as compared to higher eukaryotes; proteins a and d clearly differed from their counterparts H3 and H4 on the basis of their hydrophobic properties. The results indicate the occurrence of core histone variants in T.b. brucei which may influence DNA-histone and histone-histone interactions as well as the chromatin compaction in the nucleus of this protozoan parasite.

Complete amino acid sequence of equine miniplasminogen

The complete amino acid sequence of equine miniplasminogen (Mr 37,132, 338 residues) was determined with the aid of fragments obtained by cleavage with 2-(2-nitrophenylsulfenyl)-3-methyl-3'-bromoindolenine, cyanogen bromide or clostripain. The fragments were aligned with overlapping sequences. Sequence comparison with other species gave identities in the range of 76% (bovine) and 81% (canine), indicating the presence of the same structural and functional domains as in the other species. Sequence comparison of different miniplasminogens showed that positions 49 (Arg), 83 (Arg) and 161 (Ser) may play a role in the interaction between plasminogen and streptokinase.

Identification of the disulphide bonds in human platelet glycocalicin

The glycoprotein Ib/IX complex on platelets is responsible for the first stage of haemostasis as an essential component in the primary adhesion of platelets to damaged vessel walls. Glycocalicin is the extracellular part of platelet glycoprotein Ib alpha and contains the von Willebrand factor and thrombin binding sites. Disulphide bonds are implicated in the von Willebrand binding site and studies with peptides point towards a region of glycocalicin with four cysteines as containing the binding sites for both von Willebrand factor and thrombin. The position and linkage of these two disulphide bonds are now determined to be 209-248 and 211-264 and the relevance of this double-loop structure for glycoprotein Ib/IX function is discussed.

Primary structure of a new actin-binding protein from human seminal plasma

Secretory actin-binding protein (SABP), a glycoprotein from human seminal plasma, was isolated according to Akiyama and Kimura [Akiyama, K. & Kimura, H. (1990) Biochim. Biophys. Acta 1040, 206-210]. The complete amino acid sequence of SABP was determined with the aid of fragments generated by trypsin, Staphylococcus aureus V8 protease and pepsin. The single polypeptide chain of SABP contains 118 amino acids with a calculated Mr of 13,506 and pyroglutamic acid as the N-terminal residue. A single N-glycosidic carbohydrate moiety is located at Asn77. The carbohydrate composition shows an unusually high amount of fucose. The arrangement of the two disulfide bonds is Cys37-Cys63 and Cys61-Cys95. Sequence comparison revealed a high degree of similarity with a 14-kDa submandibular gland protein from mouse (45% identity and 64% similarity). SABP is identical with a prolactin-inducible protein and a protein termed gross cystic disease fluid protein 15 (sequences translated from cDNA clones), both from human breast tissues. Although SABP was also detected in saliva, in extracts of the submandibular gland and seminal vesicles, little is known of its function.

Identification of the disulfide bonds of human complement C1s

C1s, one of the three subcomponents of C1, the first component of the complement system, is a complex serine protease. To determine the disulfide-bonding pattern, fragments of C1s were generated by cleavage with pepsin, thermolysin, or subtilisin. Disulfide bonds have been identified by several methods, for example, direct observation of the phenylthiohydantoin derivative of cystine during Edman degradation of isolated peptides and placement in the known cDNA sequence. All of the 26 half-cystines are linked in disulfide bonds occurring at positions 50-68, 120-132, 128-141, 143-156, 160-187, 219-236, 279-326, 306-339, 344-388, 371-406, 410-534, 580-603, and 613-644. All of the disulfide bonds of the earlier described substructures of C1s, the EGF-homologous part, the two SCR units, and the two domains typical for C1s and C1r are localized within these domains.

HLA in bullous pemphigoid. The probable role of HLA-B7 as a marker for poor responders to immunosuppressive therapy

The frequency of HLA-class I and DR antigen frequencies were studied in 38 (class I) and 19 (DR) patients with bullous pemphigoid, respectively, and compared with controls. There was no important difference in the frequency of HLA-A,B,C, and DR antigens between patients and controls. An increase in the HLA-B7 frequency in poor responders to immunosuppressants (50% vs. 27% in the control group and vs. 13% in the group of all patients) was noticed, and the possible role of this antigen as a marker for poor responders to therapy was suggested.

MP38 contains the membrane-embedded domain of the lens fiber gap junction protein MP70

A 70-kDa lens membrane polypeptide (MP70) is a specific component of the fiber gap junctions. The C-terminal portion of MP70 is removed by age-related proteolytic processing, leaving an N-terminal 38-kDa polypeptide (MP38) in the membrane. Membrane association and topology of MP70 and of its processed form MP38 have been studied by hydrophobic labeling with 3-(trifluoromethyl)-3-(m-[125I]iodophenyl)diazirine and phenyl isothio[14C]cyanate. Membrane-embedded segments have been identified. They are localized in the N-terminal 30-kDa portion of MP70 and MP38. The C-terminal 40-kDa portion of MP70 appears to be exposed entirely at the cytoplasmic side of the junctional membranes. Hence, potentially poreforming peptide segments in the MP70 molecule are conserved upon age-related processing to MP38.

Interleukin-2 receptor expression and interleukin-2 production in bullous pemphigoid

Expression of interleukin-2 (IL2) receptors was studied on peripheral blood lymphocytes (PBLs) in 25 patients with bullous pemphigoid. Analysis was carried out by flow cytometry. Without immunosuppressive therapy expression of IL2 receptors only on T cells (CD5) was significantly increased as shown by double staining (11.9% +/- 7.8% vs 2.1% +/- 1% in controls). After 2-3 weeks under immunosuppressive treatment with prednisolone and azathioprine, however, BP lymphocytes did not exhibit any IL2 receptors. PBLs of 18 BP patients showed an increase in IL2 production (1027.4 +/- 670.5 U/ml vs 270 +/- 100 U/ml in controls) during the acute stage of the disease after stimulation with phytohaemagglutinin (PHA)/phorbol myristate acetate (PMA). On the contrary, IL2 production of the same cells in five patients was only in the lowest range of control values after PHA stimulation without PMA (12.5 +/- 29.6 U/ml vs 40 +/- 20 U/ml in controls). Under treatment with immunosuppressants the IL2 production normalized after PHA/PMA stimulation and slightly decreased following PHA stimulation. From these results we conclude that a T-cell activation via activation antigens, as IL2 receptors, and the production of the specific ligand, IL2, may play a role in the pathogenesis of bullous pemphigoid, especially in the earliest stages, and serve as a marker of disease activity.

Complete amino acid sequence of canine miniplasminogen

The complete amino acid sequence of canine miniplasminogen (Mr 36,678, 333 residues) was determined with the aid of fragments obtained by cleavage with BNPS-skatole, cyanogen bromide or clostripain. The fragments were aligned with overlapping sequences. Sequence comparison with miniplasminogens of other species gave identities in the range of 80% (bovine) and 88% (human), indicating the presence of the same structural and functional domains as in the other species. Sequence comparison of different miniplasminogens showed that plasminogens of species activated by streptokinase have identical residues in positions 49, 83 and 161 of the plasmin light chain. The triad of these amino acids may represent at least one of eventually several prerequisites for the interaction and activation of plasminogen with streptokinase.

[Expression of leukocyte antigens in human sperm]

The expression of leukocyte antigens on human ejaculated spermatozoa and lymphocytes was compared by means of the immunofluorescence technique and monoclonal antibodies against anti-HLA class I (pan-HLA-A,B,C) and class II (DR, DR/DP). Lymphocytes showed specific fluorescence phenomena after incubation with the antibodies. However, in the case of spermatozoa no immunofluorescent labeling was detected. Modifications of the method of sperm preparation (Ficoll centrifugation, swim-up technique, addition of azide, fetal calf serum or benzamidinchloride) did not lead to different results. We were not able to find HLA-antigen expression on fresh human spermatozoa using immunofluorescence.

Neonatal imitation of tongue protrusion and mouth opening: methodological aspects and evidence of early individual differences

The present work examines imitation of mouth opening and tongue protrusion in 32 full-term infants at three different occasions: When the infants are two to three days, three weeks, and three months old. The analysis focuses (1) on individual differences in imitative behaviour and (2) on how to operationalize the infants' responses. The overall group analysis revealed that imitation of tongue protrusion was statistically significant for both two- to three-day-old and three-week-old infants but not when the children had become three months old. No statistically significant effect was observed for imitation of mouth opening. Two different imitation indexes were constructed in order to assess individual differences in early imitative behaviour. Results show that short-term stability in imitative tendencies exists between the first and second observation. The results further reveal that methodological factors must be seriously considered when studying neonatal imitation: the overall imitation found for tongue protrusion is demonstrated to be dependent on how the infants' responses are coded.

[The behavior of membrane receptors of peripheral blood lymphocytes in bullous pemphigoid]

In 35 patients with bullous pemphigoid (BP) various parameters of the cellular immune system were studied. It was shown that the average 29% decrease in the number rosette-forming lymphocytes in sheep red blood cells is converted by the immune complexes and by a second serum factor in the acute stage of BP that has not yet been characterized precisely. These changes were reversible in patients who were placed on immunosuppressants. Obviously, this mechanism is partly due to the binding of immune complexes via Fc receptors on T-lymphocytes and is consequently due to the steral blocking of sheep erythrocyte receptors. No decrease in the number of T-cells was found by means of monoclonal antibodies (CD2, CD3), and the number of suppressor cells was also normal (CD8). On the other hand, the number of T-helper cells increased by an average of 15% (CD4). In addition, in the acute stage, there is a significant increase in the number of activation antigen Tac (CD25) and DR-bearing lymphocytes: 29% and 37% respectively (the normal values are 2% and 11%, respectively). Double staining permitted the phenotype of activated lymphocytes to be detected within the T-cells and the T-helper cell subpopulation, respectively. The number of activated T-helper cells correlates with the disease activity, and from that point it seems to be useful as a marker of activity in follow-up studies.

Lymphocytotoxic autoantibodies in progressive systemic sclerosis

In 53 patients with progressive systemic sclerosis (PSS) the lymphocytotoxic activity of their serum was measured in a microlymphocytotoxicity assay. In 21 of the 53 patients the test reacted distinctly positively in the heterologous system, and in 9 of these 21 also in the autologous system. After preparation of the immunoglobulins from these positive sera, whole cytotoxic activity was detected only in the IgM fraction but not in the IgG fraction. When using prepared T lymphocytes as target cells in the microlymphocytotoxicity test, the cytotoxic activity of the positive PSS sera showed itself to be directed against this lymphocyte population. Further analysis using the Western-blot technique showed that the IgM autoantibody in PSS sera reacted with the cell surface of CD4+ lymphocytes. The cross reactivity with extractable nuclear antigens was rather improbable. These results suggest that lymphocytotoxic autoantibodies may play a role in immunological disturbances in PSS.

The N- and O-linked carbohydrate chains of human, bovine and porcine plasminogen. Species specificity in relation to sialylation and fucosylation patterns

The structures of the N- and O-glycans of human, bovine and porcine plasminogen were determined by 500-MHz 1H-NMR spectroscopy. The N-glycans of all three species proved to be of the N-acetyllactosamine type differing from one another with respect to the sialylation and fucosylation patterns. In the N-glycan of human plasminogen the two antennae are sialylated with N-acetylneuraminic acid (NeuAc), whereas in the bovine counterpart both branches carry significant amounts of N-glycolylneuraminic acid (NeuGc). In porcine plasminogen the sialic acid is mainly NeuAc; the Man alpha 1----6 branch, however, is only partially sialylated. In addition, the porcine N-glycan is fucosylated to about 80% in alpha 1----6 linkage to the GlcNAc-1 residue. The O-glycans of the three species possess an identical Gal beta 1----3GalNAc core which is alpha 2----3 sialylated with NeuAc at Gal. The disialylated form, which is also present in all three species, has an additional NeuAc residue in alpha 2----6 linkage to GalNAc. Mono- and disialylated forms occur in different molar ratios in the different plasminogens: 80:20 in human, 70:30 in bovine and 50:50 in porcine. This study on the carbohydrate moiety of these three plasminogens reveals species specificity in terms of various types of microheterogeneities.

Complete amino acid sequence of human plasma Zn-alpha 2-glycoprotein and its homology to histocompatibility antigens

In the present study the complete amino acid sequence of human plasma Zn-alpha 2-glycoprotein was determined. This protein whose biological function is unknown consists of a single polypeptide chain of 276 amino acid residues including 8 tryptophan residues and has a pyroglutamyl residue at the amino terminus. The location of the two disulfide bonds in the polypeptide chain was also established. The three glycans, whose structure was elucidated with the aid of 500 MHz 1H NMR spectroscopy, were sialylated N-biantennas. The molecular weight calculated from the polypeptide and carbohydrate structure is 38,478, which is close to the reported value of approximately equal to 41,000 based on physicochemical measurements. The predicted secondary structure appeared to be comprised of 23% alpha-helix, 27% beta-sheet, and 22% beta-turns. The three N-glycans were found to be located in beta-turn regions. An unexpected finding was made by computer analysis of the sequence data; this revealed that Zn-alpha 2-glycoprotein is closely related to antigens of the major histocompatibility complex in amino acid sequence and in domain structure. There was an unusually high degree of sequence homology with the alpha chains of class I histocompatibility antigens. Moreover, this plasma protein was shown to be a member of the immunoglobulin gene superfamily. Zn-alpha 2-glycoprotein appears to be a truncated secretory major histocompatibility complex-related molecule, and it may have a role in the expression of the immune response.

Structural aspects of the plasminogen of various species

The N-terminal amino acid sequence of equine, ovine, canine, goat and rabbit plasminogen were determined and compared with those already known of the human, bovine, porcine and feline molecule. Furthermore, the kringle 4 domains of equine, ovine, canine and goat plasminogen, prepared by limited cleavage with elastase, were sequenced and compared with the known species of human, bovine, porcine and chicken plasminogen. Homology with the human kringle 4 ranges between 73% (chicken) and 90% (bovine). Comparison of sequences, fragmentation patterns with elastase and adsorption on lysine-Bio-Gel suggests the same structural and functional domains in the animal species as in human plasminogen.

Isolation, characterization and amino-acid sequence of gamma-seminoprotein, a glycoprotein from human seminal plasma

gamma-Seminoprotein (gamma-SM), a glycoprotein from human seminal plasma, was isolated in highly purified form by ion-exchange chromatography on a Mono Q column. The main form, fraction M, was homogeneous by PAGE at pH 8.3 and by SDS-PAGE. The complete amino acid sequence of gamma-SM was determined with the aid of fragments generated by cleavages with cyanogen bromide, clostripain, chymotrypsin and Staphylococcus aureus V8 protease. The fragments were aligned with overlapping sequences. The single polypeptide chain of gamma-SM contains 237 amino acids with a calculated Mr of 26079. A single N-linked carbohydrate side chain is attached to Asn45. The complex structure of this oligosaccharide has been determined recently [van Halbeek H. et al. (1985) Biochem. Biophys. Res. Commun. 131, 507-514]. Sequence comparison with serine proteases shows a high degree of homology, especially with the kallikrein family. The residues in the vicinity of the active site of serine proteases are also highly conserved in gamma-SM, indicating the participation of His41, Asp96 and Ser189 in its active site. gamma-SM hydrolyzed M-casein with a pH optimum at 8.0, but failed to hydrolyze any of the synthetic substrates tested. This proteolytic activity could be inhibited with diisopropylfluorophosphate, phenylmethylsulfonyl fluoride, Zn2+ or Hg2+ ions.

Isolation and characterization of the structural gene for secreted acid phosphatase from Schizosaccharomyces pombe

The Schizosaccharomyces pombe acid phosphatase structural gene (PHO 1) was isolated by complementation of an S. pombe acid phosphatase mutant with a wild type S. pombe DNA recombinant plasmid library. Northern analysis indicates that acid phosphatase is encoded by a 1.4-kilobase mRNA of which approximately 100 bases are 3'-poly(A). The gene contains no introns and the 3' and 5' untranslated regions are short. According to DNA and amino acid sequence data, the S. pombe acid phosphatase has a molecular weight of 50,600. An 18-amino acid sequence at the N terminus was found that is similar to previously identified signal peptides in other eukaryotic secretory proteins. This signal peptide is apparently removed during secretion, since it is absent in the mature secreted acid phosphatase. The gene can be induced 2--3-fold by starvation for phosphate. The signals required for this induction are contained on the isolated DNA clone. Although the gene can be expressed in Saccharomyces cerevisiae, secretion is abnormal.