Conversion of pyridylamino sugar chains to corresponding reducing sugar chains

Pyridylamino sugar chains were converted to the corresponding reducing sugar chains by first converting them to 1-amino-1-deoxy derivatives using the method previously reported [S. Hase, J. Biochem. 112, 266-268 (1992)] and then converting the products to the corresponding reducing sugar chains using the Sommlet reaction. The reaction conditions were optimized so as to obtain the maximal product yield using 1-amino-1-deoxylactose and 1-amino-1-deoxy-N-acetylglucosamine. When the established procedure was successively applied to pyridylamino high-mannose and complex-type sugar chains, the corresponding reducing sugar chains were obtained in yields of 30%.     

Monitoring of trophic chains

In the paper simple trophic chains of the type resource-producer-primary consumer are considered. For an analysis of the dynamic state monitoring of this system, the concept of observability of mathematical systems theory is proposed. Using a linearization method of non-linear observation systems, biologically interpretable sufficient conditions are obtained to guarantee local observability. The latter means that based on the dynamic observation of a single component, the state of the whole system can be uniquely recovered, at least near a positive equilibrium.     

Ubiquitin in chains

The ubiquitin-proteasome system fulfills an essential function in eukaryotes by controlling the levels of crucial intracellular regulatory proteins. In this system, a specific type of polyubiquitin chain acts as the proximal signal for targeting substrates to 26S proteasomes for degradation. Recent results have revealed important determinants of polyubiquitin-chain recognition by proteasomes, helping to explain the biological rationale behind this novel signaling mechanism.     

Linear polyubiquitin chains

The ubiquitin conjugation system regulates a wide variety of biological phenomena, including protein degradation and signal transduction, by regulating protein function via polyubiquitin conjugation in most cases. Several types of polyubiquitin chains exist in cells, and the type of polyubiquitin chain conjugated to a protein seems to determine how that protein is regulated. We identified a novel linear polyubiquitin chain and the ubiquitin-protein ligase complex that assembles it, designated LUBAC. Both were shown to have crucial roles in the canonical NFκB activation pathway. This year, three groups, including our laboratory, identified SHARPIN as a new subunit of LUBAC. Of great interest, Sharpin was identified as a causative gene of chronic proliferative dermatitis in mice (cpdm), which is characterized by numerous inflammatory symptoms including chronic dermatitis, arthritis and immune disorders. Deletion of SHARPIN drastically reduces the amount of LUBAC and attenuates signal-induced NFκB activation. The pleomorphic symptoms of cpdm mice suggest that LUBAC-mediated NFκB activation may play critical roles in mammals and be involved in various disorders. A forward look into the linear polyubiquitin research is also discussed.     

Living macrophages phosphorylate the 20,000 dalton light chains and heavy chains of myosin

Brief incubation of rabbit alveolar macrophages in medium containing ³²Pi results in the incorporation of radioactivity into the 20 KD light chains and into the 220 KD heavy chains of myosin. Phosphorylation of the heavy chain is mediated by a kinase that is probably not myosin light chain kinase. Limited proteolysis of the phosphorylated myosin shows that radioactivity is associated with the rod portion of the heavy chain.     

Phosphorylation of vertebrate nonmuscle and smooth muscle myosin heavy chains and light chains

In this article we review the various amino acids present in vertebrate nonmuscle and smooth muscle myosin that can undergo phosphorylation. The sites for phosphorylation in the 20 kD myosin light chain include serine-19 and threonine-18 which are substrates for myosin light chain kinase and serine-1 and/or-2 and threonine-9 which are substrates for protein kinase C. The sites in vertebrate smooth muscle and nonmuscle myosin heavy chains that can be phosphorylated by protein kinase C and casein kinase II are also summarized.Original data indicating that treatment of human T-lymphocytes (Jurkat cell line) with phorbol 12-myristate 13-acetate results in phosphorylation of both the 20 kD myosin light chain as well as the 200 kD myosin heavy chain is presented. We identified the amino acids phosphorylated in the human T-lymphocytes myosin light chains as serine-1 or serine-2 and in the myosin heavy chains as serine-1917 by 1-dimensional isoelectric focusing of tryptic phosphopeptides. Untreated T-lymphocytes contain phosphate in the serine-19 residue of teh myosin light chain and in a residue tentatively identified as serine-1944 in the myosin heavy chain.Abbreviations MLC myosin light chain - MHC myosin heavy chain - Tris tris(hydroxymethyl)aminomethane - EGTA [ethylenebis(oxyethylenenitrilo)]tetraacetic acid - EDTA ethylenediaminetetraacetate - TPCK N-tosyl-L-phenylalanine chloromethyl ketone - PMA phorbol 12-myristate 13-acetate     

Polyunsaturated hydrocarbon chains: computer study of the characteristics of intramolecular ordering of chains

The conformational properties of isolated unbranched hydrocarbon polyunsaturated molecules of cis-C18:4 and cis-C18:5 under theta-conditions (T = 298 K) were studied using Monte Carlo simulations. The conformations were generated by a computer (the continuum model was used; the energy of nonbonded interactions and torsion and electrostatic terms were taken into account). A molecule-fixed coordinate system with the axes along inertia tensor eigenvectors of each molecule conformation (principal axes of inertia) were used for the calculations. C-H and C-C bond orientation distribution functions rho and ordering parameters S with respect to the maximum molecule span axis were calculated. It was shown that the presence of five methylene-interrupted cis double bonds in C18 chain has a maximum effect on the intramolecular ordering properties of the molecule. The widths of function rho CH for pentaenes differed significantly from those of other C18-chains: the widths of function rho for all CH2-groups were nearly twice as large as that for C-H-bonds flanking the double bonds C=C, and roughly constant along the chain sequence. The mean magnitudes of magnitudes of SCH in the molecule decreased when unsaturation increased.     

Different asparagine-linked sugar chains on the two polypeptide chains of human chorionic gonadotropin

Human chorionic gonadotropin (hCG) purified from placenta, like urinary hCG, is shown to have the sialylated forms of three neutral oligosaccharides: Galβ1→4GlcNAcβ1→2Manα1→6(Galβ1→4GlcNAcβ1→2Manα1→3)Manβ1→4GlcNAcβ1→4(Fucα1→6)GlcNAc (N-1), Galβ1→4GlcNAcβ1→2Manα1→6(Galβ1→4GlcNAcβ1→2Manα1→3)Manβ1→4GlcNAcβ1→4GlcNAc (N-2) and Manα1→6(Galβ1→4GlcNAcβ1→2Manα1→3)Manβ1→4GlcNAcβ1→4GlcNAc (N-3). Gel permeation chromatographic analysis of oligosaccharides released from α- and β-subunits of placental hCG has revealed that the α-subunit has one each of sialylated N-2 and N-3, while the β-subunit has one each of sialylated N-1 and N-2.     

A component of the fraction of porcine light chains structurally related to heavy chains

In the previous paper (Rejneket al., 1967) we described the fractionation of light chains (L) by Zn ions resulting in an accumulation of antigenic determinants of the heavy chain (H) in the Zn precipitate. Peptide maps of the obtained fractions of the L chains differ considerably from each other. Peptides of the L chains, the position of which corresponds within the experimental error to peptides of the H chain may be detected by comparing them with the peptide map of the H chains. The number of such peptides increases with qualitatively assayed accumulation of the component precipitated with anti-H serum during fractionation. The concentration of N-terminal glutamic acid, characteristic for the H chains increases at the same time.     

On chains of related sets

IfK is a partition of a setK which is partially ordered by the relationR andR is a collection of pairs of sets ofK such that the sets of each pair are related byR in the sense of Rashevsky, thenR is a relation which partially ordersK. Necessary and sufficient conditions thatK be a chain are obtained, and ifK is a chain under these conditions, it is shown thatK is unique.     

Optical anisotropy of polypeptide chains

Optical anisotropies γ² of N-t-butylacetamide (tBA), N-Methylacetamide (MA), and N, N-dimethylacetamide (DMA) have been determined from the Rayleigh ratios for depolarzed scattering by dilute solutions of the amides in p-dioxane. Traceless optical polarizability tensors \documentclass{article}\pagestyle{empty}\begin{document}$ \widehat{\rm \alpha } $\end{document} for the amides are derived from these results in conjunction with the Kerr constant for tBA determined by LeGèvre and co-workers. It is shown that the tensor \documentclass{article}\pagestyle{empty}\begin{document}$ \widehat{\rm \alpha } $\end{document}_i for the glycyle unit in a polypeptide chain may be identified with \documentclass{article}\pagestyle{empty}\begin{document}$ \widehat{\rm \alpha } $\end{document}MA . Methods for deriving corresponding tensors for other peptide units are indicated and the traceless polarizability tensor \documentclass{article}\pagestyle{empty}\begin{document}$ \widehat{\rm \alpha } $\end{document} for a polypeptide chain in any specified configuration is formulated.