Human histidine-rich glycoprotein: simultaneous purification with antithrombin III and characterization of its gross structure

The simple and simultaneous purification of histidine-rich glycoprotein (HRG) and antithrombin III (AT III) from human plasma and gross structural characterization of HRG have been performed. The purification method consists of two chromatographic procedures using heparin-agarose and DEAE-Sephadex. The yields of HRG and AT III were 22 mg and 70 mg, respectively, from 1 liter of plasma. The purified HRG is a single-chain polypeptide with a molecular weight (Mr) of 75,000 on sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis, indicating it was the native form of this protein. Cyanogen bromide cleavage of HRG, followed by analysis of the amino acid composition and determination of the amino-terminal sequence of each purified cyanogen bromide fragment established that the gross structure of HRG consisted of three cyanogen bromide fragments; an amino-terminal CN-50 kDa fragment (Mr 50,000) and a carboxy-terminal small fragment of eight amino acids, and a CN-30 kDa fragment (Mr 30,000) between them. As to the amino acid composition of the CN-30 kDa fragment, it had an unusually high content of histidine (25 mol%), suggesting the presence of a histidine-rich region(s) in the carboxy-terminal half of the molecule. These results together with our previous results (Koide, T., Odani, S., & Ono, T. (1982) FEBS Lett. 141, 222-224) and those of Morgan (Morgan, W.T. (1985) Biochemistry 24, 1496-1501) imply that HRG is composed of at least two domains with distinct functional properties; i.e. an amino-terminal domain with heparin-binding ability and a carboxy-terminal domain with heme- and divalent metal-binding abilities.     

Sorbitol determination by liquid chromatography: application to red blood cells of diabetic rats

This report describes an application of liquid chromatography to the determination of sorbitol in red blood cells. The chromatograph employed in the present study was made up of sub- and main-separation systems and a detector portion. The sub-separation system was for concentration of polyols and involved two small columns, each containing the same anion exchange resin. The first was a tiny column which, in borate form, served as the concentrator of polyols and sugars charged in a large volume, while the second, in acetate form, separated the carbohydrates from the borate. The main system was for the fine separation of each carbohydrate and employed cation exchange columns. The detector part utilized a flow fluorometric method comprising two successive reactions: periodate oxidation followed by the Hantzsch reaction. The resulting whole chromatographic system was applied to the determination of sorbitol in red blood cells obtained from normal rats and rats made diabetic by the administration of streptozotocin; a part of the latter group had also received an aldose reductase inhibitor. Our results supported the concepts that a prolonged duration of high blood glucose level induces an elevated level of sorbitol inside red blood cells and that aldose reductase inhibitors are effective in reducing this level.     

Role of N-acetyl-D-galactosamine residue on B151K12-derived T cell-replacing factor (B151-TRF) molecule in B cell-receptor binding and -stimulating activity

The role of sugar moiety on T cell-replacing factor molecule derived from a monoclonal T cell hybridoma B151K12 (B151-TRF) was analyzed with respect to the interaction with receptor on B cells. The induction of B cell differentiation into Ig-secreting cells by B151-TRF was specifically inhibited by addition of N-acetyl-D-galactosamine (GalNAc) to culture. Such inhibition appeared to be attributed to the interference of GalNAc in the interaction of TRF with its receptor, because absorption of TRF activity with B cells was notably inhibited by the presence of GalNAc. To substantiate this point further, we established binding assay of B151-TRF molecule to the receptor on B cells by using 125I-labeled TRF fraction enriched by reversed-phase high-performance liquid chromatography and gel filtration. The results revealed that the binding of 125I-TRF molecule to the B cells was almost completely blocked by GalNAc. Moreover, the existence of GalNAc residue(s) on B151-TRF molecule was evidenced by the facts that 1) the TRF activity was eluted from lectin gels with specificity for GalNAc as revealed by the functional assay, and 2) the 125I-TRF molecule specifically bound to such lectin gels. Thus, the GalNAc residue(s) on B151-TRF molecule plays an important role in binding of TRF molecule to the receptor and in the stimulation of B cells. The molecular properties of B cell-stimulatory B151-TRF and its mode of interaction with corresponding receptor on B cells were discussed in the context of B151-TRF as a glycosylated lymphokine molecule and B151-TRF receptor as a carbohydrate-binding protein (animal lectin).     

IL-6 activity in feline infectious peritonitis

Involvement of IL-6 in the development of vasculitis and polyclonal gammopathy in feline infectious peritonitis (FIP) was investigated, by using the proliferative responses of two IL-6-dependent murine hybridoma cell clones, B3B1 and MH60.BSF-2 cells. A significant IL-6 activity was found in sera and ascitic fluids of cats with FIP, whereas no IL-6 activity was detected in sera from healthy cats. In these FIP cats, IL-6 activity in ascitic fluids was significantly higher than that in sera. Peritoneal exudate cells from FIP cats were also found to release a high level of IL-6 to the culture supernatant. The ascitic IL-6 activity was eluted into the fractions corresponding to the m.w. of 30,000 to 40,000 in gel filtration, and into the fractions at the salt concentration from 0.2 to 0.3 M NaCl in anion exchange chromatography. The level of ascitic IL-6 activity was inversely correlated to serum albumin/globulin ratio in these FIP cats. These findings indicate that IL-6 accumulated in the ascites might leaked into the systemic circulation, and be linked to systemic alterations such as enhanced synthesis of Ig and acute phase proteins.     

``alternative Self-Diploidization'''' or ``asd'''' Homothallism in Saccharomyces Cerevisiae: Isolation of a Mutant, Nuclear-Cytoplasmic Interaction and Endomitotic Diploidization

A mutant of Saccharomyces cerevisiae representing a novel life cycle, named "alternative self-diploidization" or "ASD" homothallism, was obtained fortuitously. In this life cycle, MAT alpha (or MATa) haplophase and MAT alpha/MAT alpha (or MATa/MATa) diplophase alternate. Germinated cells are haploid and mating. They soon become nonmating and sporogenous as they vegetatively grow. They sooner or later diploidize presumably via endomitosis. The diploid cells haploidize via normal meiosis. A single recessive nuclear mutation, named asd 1-1, is responsible for "ASD" homothallism. In the rho 0 cytoplasm, asd 1-1 cells mate even if at a low efficiency and fail to diploidize. Since pet mutations do not have such effects, we conclude that a certain mitochondrial function other than respiration is required for manifestation of "ASD" homothallism. That is, "ASD" homothallism is the result of some sort of nuclear-cytoplasmic interaction.     

Mn K-edge XANES spectroscopy of a photosynthetic O2-evolving complex. High-quality pre-edge features and distinct fine structures in the S1- and S2-states

High-resolution XANES (X-ray Absorption Near Edge Structure) spectroscopy for Mn in the S1 and S2 states of the spinach photosynthetic O2-evolving complex revealed distinct features in K-edge spectra, when a high signal-to-noise (S/N) ratio of ca. 80 with a low and constant background-to-signal (B/S) ratio of 0.15 to 0.18 was attained. Six features resolved in each S-state spectrum involve a pre-edge feature due to 1s----3d transitions, a main-edge feature possibly due to 1s----4s transitions and four fine structures superimposed on the principal absorption bands due to 1s----4p* transitions. The high-quality pre-edge features were analyzed according to a parametric ligand-field theory in comparison with those of some typical authentic Mn complexes. It was deduced that i) all of the four Mn ions in the S1-state are octahedrally coordinated and two of them constitute a di-mu-oxo bridged Mn(III, III) dimeric subunit; ii) the bridged Mn(III) ions are further bridged by a deprotonated water dimer, (HOHOH)-, and coordinated by imidazole-N and carboxylate-O- on the opposite side of the Mn atom from the di-mu-oxo bridge; iii) the other two Mn ions exist in the form of Mn(III) monomeric subunits; and iv) upon the S1----S2 transition, only the bridged Mn(III,III) is oxidized to Mn(III,IV). The distinct change in the principal absorption band shape upon the S1----S2 transition is briefly discussed to obtain the XANES evidence for a tetrameric Mn-cluster.     

Nucleotide sequence and characteristics of the gene for L-lactate dehydrogenase of Thermus aquaticus YT-1 and the deduced amino acid sequence of the enzyme

The gene for L-lactate dehydrogenase (LDH) from Thermus aquaticus YT-1 was cloned in Escherichia coli, using the Thermus caldophilus LDH gene as a hybridization probe, and its complete nucleotide sequence was determined. The LDH gene comprised 930 base pairs, starting with a GTG initiation codon. Its sequence had high homology (85.8% identity) with the LDH gene of T. caldophilus. The G + C content of the T. aquaticus gene was 70.9%, higher than that of the chromosomal DNA (67.4%). In particular, that in the third position of the codons used was 91.0%, similar to the T. caldophilus gene. The primary structure of T. aquaticus LDH was deduced from the nucleotide sequence of the LDH gene. It comprises 310 amino acid residues, as does T. caldophilus LDH, and its molecular mass was calculated to be 33,210 daltons. The amino acid sequence of the T. aquaticus LDH had 87.1% identity with that of the T. caldophilus LDH. At 23 positions, the respective residues differed in charge and polarity. These differences must be related to the differences in kinetic properties between the two enzymes. The constructed plasmid overproduced the T. aquaticus LDH in E. coli.     

Structure and expression of cDNA for D-amino acid oxidase active against cephalosporin C from Fusarium solani

D-Amino acid oxidase (DAO) was extracted and purified from cultured mycelia of Fusarium solani M-0718 (FERM P-2688). The enzyme was able to oxidatively deaminate cephalosporin C to 7-beta-(5-carboxy-5-oxopentanamido)cephalosporanic acid. Ninety-eight amino acid residues of the F. solani DAO were determined by sequence analysis of 9 peptides derived from Acromobacter protease I digests of the protein. Complementary DNAs encoding F. solani DAO were isolated from the F. solani cDNA library by hybridization with synthetic oligonucleotide probes corresponding to the partial amino acid sequences. Analysis of the nucleotide sequences of the clones revealed a 1,186-nucleotide sequence with a 5'-terminal untranslated region of 41 nucleotides, an open reading frame of 1,083 nucleotides that encoded 361 amino acids, and a 3'-terminal untranslated region of 62 nucleotides. The amino acid sequence of F. solani DAO had 25% homology to that of porcine kidney DAO [EC 1.4.3.3] and 37% homology to that of Trigonopsis variabilis DAO. The constructed plasmid overproduced F. solani DAO in Escherichia coli. The recombinant DAO had almost the same molecular activity as the native DAO against cephalosporin C.     

Ultrastructural changes during lysis of L929 target cells by class II-restricted influenza virus-specific murine cytotoxic T-lymphocyte clones

Lysis of virus-infected L929 target cells transfected with the H-2 class II IAk gene by class II-restricted influenza virus-specific murine cytotoxic T lymphocyte (CTL) clones was studied by electron microscopy and compared with lysis of L929 cells by class I-restricted CTL clones. T lymphocytes predominantly approached the basal surface of target cells grown on a plastic dish and also approached uninfected L929 target cells, although virus maturation exhibited no polarity with respect to the cell surface site. After incubation for 30 min, the target cell nuclei began to change: chromatin became irregularly redistributed and aggregated, and the nuclei appeared swollen. Later, electron-dense and -light areas of nuclei became segregated, and the cytoplasm became disorganized with many vacuoles. The ultrastructural changes of target cells during lysis by class I- and class II-restricted CTL clones appeared to be similar. These findings and other cytotoxicity data of class I and class II CTLs are discussed.     

Molecular basis for determining the sensitivity of eucaryotes to the antimitotic drug rhizoxin

Summary Rhizoxin, an antibiotic, exhibits potent anti-mitotic activity against most eucaryotic cells including those of higher vertebrates, plants and fungi by binding to -tubulin. ThebenA gene of three independently isolated rhizoxin-resistant (Rhi^r) mutants ofAspergillus nidulans was cloned, sequenced and compared with that of the wild-type, rhizoxin-sensitive (Rhi^s) strain. In all three Rhi^r mutants, the AAC codon for Asn-100 of thebenA -tubulin gene was altered to ATC, coding for Ile. Sequence displacement experiments confirmed that the substitution of Ile for Asn-100 confers resistance to rhizoxin in this organism. The amino acid sequences of -tubulin surrounding the 100th amino acid residue from the N-terminus including Asn-100 are highly conserved with a few exceptions. The fission yeastSchizosaccharomyces pombe and the budding yeastSaccharomyces cerevisiae are naturally occurring Rhi^r organisms whose -tubulin genes encode Ile and Val respectively at the 100th amino acid residue. The Ile-100 ofS. pombe and the Val-100 ofS. cerevisiae were altered to Asn using site-directed mutagenesis and gene displacement techniques. The resultant haploid strains of these two yeasts uniquely expressing -tubulin (Asn-100) instead of -tubulin (Ile-100 or Val-100) were found to be Rhi^s. Haploid yeast expressing -tubulin (Asn-100) is normal except for its sensitivity to rhizoxin. These results suggest that rhizoxin resistance has a common basis in both naturally occurring species and experimentally selected mutants in the substitution of Ile or Val for Asn-100 in -tubulin.