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E A Robinson

Publications and source records attributed to E A Robinson.

At least 73 records · Page 4Linked to original sources
PubMed1980

Messenger RNA coding for the deleted heavy chain of mouse myeloma MOPC 47A immunoglobulin.

Mouse IgA 47A is an immunoglobulin variant whose heavy (alpha) chain has a molecular weight of 40,000 and lacks the entire CH3 domain. In order to understand better the mechanism by which the CH3 domain is lost, the 47A heavy chain mRNA has been partially purified. The mRNA migrated as a 17 S species on sucrose gradients and coded for the cell-free synthesis of only one serologically reactive protein with an apparent molecular weight of 42,000. Competitive inhibition of immunoprecipitation and tryptic peptide analysis of a cyanogen bromide fragment of the in vitro product revealed significant homology between the authentically secreted heavy chain and the respective cell-free synthesized, immunoprecipitated product. The heavy chain mRNA of 47A possessed a chain length of about 2200 nucleotides which is the same size as a normal alpha heavy chain mRNA, thus demonstrating that the protein deletion is not due to a large deletion at the mRNA level. The deletion in the 47A heavy chain may be due to a frameshift of a single nucleotide followed by premature chain termination.

Animals↗
PubMed1980

Complete amino acid sequence of a mouse immunoglobulin alpha chain (MOPC 511).

The complete amino acid sequence of the 432-residue heavy (alpha) chain of mouse myeloma MOPC 511 has been determined. The variable region of the alpha chain of IgA 511, a phosphocholine-binding protein, is highly homologous to that of the other phosphocholine-binding immunoglobulins. Comparison of the 511 alpha chain constant region with that of other mouse and human heavy chains shows that sequence divain. The CH3 domain disulfide bridge of the 511 alpha chain, for example, consists of only 28 amino acid residues compared to 60 residues for other chains and domains. Sequence divergences are alsos apparent at the CH2/CH3 domain boundary, an area where a number of frameshift mutations have occurred. One mutant, mouse IgA 47A, lacks the entire CH3 domain. Comparison of the 511 alppha chain with the 47A alpha chain reveals two noncconservative amino acid changes at the COOH terminus of the 47A chain, Ser-Gln for VAl-Thr in the 511 chain. These changes and the deletion of the CH3 domain can be explained by a single genetic event--namely, a frameshift mutation followed by premature chain termination. The remainder of the 47A constant region, including the hinge region, is identical to the 511 alpha chain, except for two conservative changes in the CH1 domain: serine-126 and theonine-197 in the 511 alpha chain are both replaced by alanine in the 47A chain.

Amino Acid Sequence↗
PubMed1980

Citrate induced hypocalcaemia during cell separation.

The value of calcium addition during cell-separation by the Haemonetics Model 30 has been investigated in two patient groups. Where citrated plasma was used as the replacement fluid the addition of calcium abolished clinical symptoms and reduced the degree of citrate induced hypocalcaemia. When Plasma Protein Fraction was used as the replacement fluid, calcium addition was not necessary as clinical symptoms and significant hypocalcaemia did not occur.

Calcium↗
PubMed1979

The purification of murine histocompatibility antigens (H-2b) from RBL-5 tumor cells using detergents.

A detergent-solubilized form of H-2b (dH-2b) has been purified 1500-fold from RBL-5 tumor cells. The purification was accomplished by deoxycholate solubilization of purified plasma membranes, gel filtration, Lens culinaris lectin affinity chromatography, and affinity chromatography on a sheep anti-dH-2b immunoadsorbent. Both alloantigen and beta 2-microglobulin were monitored by radioimmunoassay during purification. The final product was judged to be greater than 90% pure by the following criteria: 1) sodium dodecyl sulfate-polyacrylamide electrophoresis which showed the expected 2-component structure of histocompatibility antigens, i.e. a heavy chain and beta 2-microglobulin; 2) amino acid composition which was comparable to the known compositions of other H-2 and HLA molecules; 3) NH2-terminal sequencing which gave a unique sequence for the heavy chain, and the reported sequence for beta 2-microglobulin; and 4) immunoprecipitation of the bulk of the preparation by appropriate alloantisera.

Amino Acid Sequence↗
PubMed1979

Purification and chemical characterization of papain-solubilized histocompatibility-2 antigens from mouse liver.

A large scale purification of histocompatibility-2 (H-2) antigens from mouse liver is described. The antigens were solubilized by a limited papain digestion of a crude preparation of liver membranes (strain A/J) and purified by ion exchange chromatography, gel filtration, affinity chromatography, and isoelectric focusing. The overall degree of purification of H-2Kk was 1,300-fold and that of H-2Dd was 1,500-fold; approximately 8 mg of purified H-2a antigens were obtained from 1 kg of liver. The purification was followed by a sensitive radioimmunoassay in which H-2a-containing fractions were used to inhibit the binding of 125I-labeled H-2a to appropriate antisera. H-2Dd and H-2Kk co-purified through all the steps but the concentration of H-2Kk was 2- to 3-fold higher than that of H-2Dd in the liver homogenate as well as in the purified H-2 preparation. beta 2-microglobulin was initially present in a 3- to 10-fold excess over H-2 in the liver homogenate, but the purified H-2 preparation contained approximately 2 mol of alloantigenic heavy chain/mol of beta 2-microglobulin. Isoelectric focusing and disc-gel electrophoresis showed a charge heterogeneity of H-2, with a mean isoelectric point of pH 4.9. Electrophoresis on sodium dodecyl sulfate gels showed one band. Denaturing conditions were required to remove beta 2-microglobulin and small amounts of impurities from H-2. The amino acid sequence of the first 27 residues of the isolated heavy chains was determined.

Amino Acid Sequence↗
PubMed1979

Cell-free synthesis of mouse H-2 histocompatibility antigens.

The mRNAs coding for the histocompatibility (H-2) antigens of the mouse have been identified by cell-free translation of poly(A)-containing RNA obtained from the livers of mice (strain A/J), followed by immunoprecipitation of the cell-free products by using an antiserum directed against purified H-2a. Unlike the 47,000- and 46,000-Mr H-2 glycoproteins synthesized in splenic lymphocytes, the cell-free translation products have Mrs of 45,000 and 44,500, representing the unglycosylated forms of these antigens. The cell-free products are shown to be related to the H-2 antigens by competition immunoprecipitation with purified H-2a and by two-dimensional tryptic peptide mapping. The H-2 mRNAs which sediment at 17 S are found associated predominantly with membrane-bound polysomes and are actively translated in the liver where as many as 16 ribosomes are associated with each molecule of H-2 mRNA. The implications of these studies for molecular cloning and for an understanding of the organization and expression of the genes encoding these H-2 antigens are discussed.

Animals↗
PubMed1978

Structural characterization of H-2 antigens purified from mouse liver.

Papain solubilized H-2a histocompatibility antigens (H-2Kk plus H-2Dd) have been purified by a large-scale procedure that can routinely provide 2-3 mg of heavy chain from 1 kg of mouse liver. The heavy chains were homogeneous by sodium dodecyl sulfate electrophoresis. Disc gel electrophoresis resolved two protein bands that were identified as H-2Dd and H-2Kd by immune complex formation and autoradiography. Comparative amino acid composition and NH2-terminal sequence analyses of unfractionated H-2a, H-2Kk, and HLA suggested close structural relationships. However, the following observations suggest that papain cleaves these membrane bound antigens at different positions with respect to the COOH terminus: the molecular weight of the peptide portion of papain solubilized HLA is smaller than that of H-2 (30,000 versus 33,700); the COOH-terminal sequences are different; and, finally, papain-solubilized H-2 contains a free cysteine residue in addition to the two disulfide bridges that are present in both H-2 and HLA.

Amino Acid Sequence↗
PubMed1978

Effects of a marriage enrichment program: an outcome study.

This study investigated the impact of a marriage enrichment program. Fourteen couples were randomly assigned to one of two experimental groups or to a no-treatment control group. One experimental group received fair-fight training for 3 weeks followed by a sexual enhancement format for 3 additional weeks. The second experimental groups received the opposite treatment sequence. The same counselor team used the same exercises in both groups. The sequence of treatment did not differentially affect outcome. The immediate and longer term treatment effects that were found generally favored the treatment groups over the no-treatment control group on spouses' separate reports of marital and personal functioning. Using larger and more homogeneous samples, future studies should examine the relationship of individual partner changes to couple changes, conduct a follow-up evaluation of at least 3 months, and obtain behavioral assessments of couples' interactions before and after treatment.

Aggression↗
PubMed1978

The phenotype Ae1B: a probable result of chimerism.

An apparently normal healthy adult with the blood group phenotype Ae1B is described. The unusual ABO group is apparently the result of chimerism, the proportion of the minor population of cells being so small as to be only detectable by absorption and elution techniques.

ABO Blood-Group System↗
PubMed1977

Amino acid sequence of the first 217 residues of a mouse heavy chain (MOPC 47A) with a domain deletion.

Cyanogen bromide cleavage of the deleted heavy (alpha) chain of mouse IgA 47A yielded five peptides, CNBr 1-5, consisting of 34, 50, 28, 70, and 160 residues. A 217-residue NH2-terminal sequence, which comprises the variable region and the first domain of the constant region (CH1), and a 19-residue COOH-terminal sequence of the chain were obtained from the sequences of CNBr 1-4 and the NH2-terminal and COOH-terminal sequences of CNBr 5. The tryptic peptides of the remainder of the chain have been partially characterized. Comparison of these data with the sequences of other, nondeleted, chains reveals that the 47A chain terminates exactly at the end of the CH2 domain and that there are no deletions up to that point. It is concluded that the deletion in the chain is a single, large deletion consisting of the entire CH3 domain. The 47A chain also differs from other, nondeleted, mouse alpha chains derived from BALB/c strains in that it contains a labile cysteine at position 135, which is believed to participate in the light-heavy chain bond, and contains galactosamine in the hinge region. This may mean that the 47A alpha chain, in addition to being deleted, represents a mouse IgA subclass analogous to human IgA1.

Amino Acid Sequence↗
PubMed1976

Effects of a marathon group on self-actualization and attitudes toward women.

This study investigated the impact of a 16-hour marathon session on levels of self-actualization and attitudes toward women both 1 day and 5 weeks after the group experience. Female undergraduates were assigned randomly to one of two marathon groups or to a no-treatment control group. Ss in both marathon groups experienced a significant shift toward increased independence or self-supportedness on both posttests. However, a differential group effect was found from separate comparisons of each marathon group with the control group reflected significantly shifts in attitudes toward women; Ss in one marathon group reflected significantly greater agreement with profeminist attitudes on the first posttest and experienced an even greater shift in that direction on the second posttest, while Ss in the other marathon group did not differ significantly from the control Ss on either posttest.

Attitude↗
PubMed1975

Interaction of guanosine nucleotides with elongation factor 2. I. Equilibrium dialysis studies.

Binding of the guanosine nucleotides, GDP and GTP, to elongation factor 2 (EF-2) from rat liver was studied by equilibrium dialysis. It was found that the enzyme has one binding site for GDP with a dissociation constant of 4 times 10--7 M. The examination of GTP binding was difficult due to the simultaneous presence of GDP and GTP even in purified GTP preparations. This problem was further magnified by traces of GTPase in the enzyme preparation. However, by analyzing the incubation mixtures by thin layer chromatography the fraction of the total nucleotide binding to EF-2 which was due to GDP could be determined and corrected for. A GTP binding curve, corrected for GDP binding, and GTP hydrolysis extrapolated to one binding site with a dissociation constant of approximately 2 times 10--6 M. The nonhydrolyzable GTP analogue, theta, gamma-methylene-guanosine-5-triphosphate, also bound to EF-2 in a 1:1 ratio. During the studies of GTP binding to EF-2 it was observed that the enzyme preparation contained a GTP-GDP transphosphorylase activity. It was initially thought that this was a novel property of EF-2, but when the activity was followed during purification of EF-2 it was whown that it was an impurity in the EF-2 preparation. ATP as well as GTP can serve as a phosphate donor in the transphosphorylation reaction; this might suggest that regeneration of GTP from GDP can take place via this pathway.

Animals↗
PubMed1975

Interaction of guanosine nucleotides with elongation factor 2. II. Effect of ribosomes and magnesium ions on guanosine diphosphate and guanosine triphosphate binding to the enzyme.

The effects of ribosomes and Mg-2plus on the binding of GDP and GTP to elongation factor 2 (EF-2) have been studied by an improved filter-binding assay. Both ribosomes and Mg-2plus strongly inhibit the binding of GDP but have apparently no effect on the GTP binding to the enzyme. An apparent stimulation by ribosomes of GTP binding to EF-2 is time-dependent and parallels a concomitant increase of the GDP concentration in the incubation mixture. Based on these results and evidence obtained by other investigators it is suggested that changes in the GTP:GDP ratio associated with the elongation and termination reactions of protein synthesis cause conformational changes of the respective factors which consequently will modulate the binding and dissociation of the enzymes from ribosomes. Further evidence of the role GDP may play as a modulator of protein synthesis might possibly be provided by studies of the GTP-GDP transphosphorylase activity which is present as an impurity in highly purified preparations of EF-2 as well as in ribosome preparations. It is demonstrated that relatively high concentrations of GDP in the presence of GTP completely block the ribosome-dependent GTPase activity of EF-2. Instead, the transphosphorylase enzyme(s) catalyzes an exchange reaction between GTP and GDP during which GDP remains bound to EF-2 and the relative concentrations of the two nucleotides do not change.

Animals↗