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W C Mahoney

Publications and source records attributed to W C Mahoney.

At least 37 records · Page 2Linked to original sources
PubMed1983

The amino acid sequence of D-ribose-binding protein from Escherichia coli K12.

The amino acid sequence of the D-ribose-binding protein from Escherichia coli K12 was determined from the DNA sequence of the gene. Protein sequence analyses covering 80% of the protein were consistent with the sequence deduced from the DNA. The mature binding protein has 271 amino acid residues and shows substantial homology to D-galactose-binding protein. A signal peptide sequence of 23 or 25 residues was also deduced from the DNA sequence. It shows the characteristic features of prokaryotic signal peptides.

Amino Acid Sequence↗
PubMed1983

The complete amino acid sequence of rabbit muscle phosphoglucomutase.

The complete amino acid sequence of rabbit muscle phosphoglucomutase has been determined by isolating the 11 peptide fragments produced by the cyanogen bromide cleavage reaction and subjecting these to automated sequencing procedures. Products produced by treatment of some of these fragments with hydroxylamine, iodosobenzoic acid, mild acid, cyanogen bromide in formic and heptafluorobutyric acids, Staphylococcus aureus V8 protease, and trypsin (with or without blocking at lysine residues) were used to complete the sequence for each of the cyanogen bromide fragments. The cyanogen bromide fragments were ordered by isolating the four tryptic peptides produced by a limited tryptic digest of the native enzyme in the presence of its substrates and its bivalent metal ion activator, Mg2+, degrading these by means of trypsin, after blocking digestion at lysine residues, and isolating and identifying all fragments thus produced that contained 10 or more residues. The 561-residue sequence thus obtained is one of the longest that has been determined by chemical means. There is excellent agreement between this sequence and published compositions after appropriate normalization. The absorbance of the enzyme is about 7.0 at 278 nm for a 1% solution; this value is 9% lower than that previously used.

Amino Acid Sequence↗
PubMed1982

Human hypoxanthine-guanine phosphoribosyltransferase. Complete amino acid sequence of the erythrocyte enzyme.

The entire amino acid sequence of hypoxanthine-guanine phosphoribosyltransferase from human erythrocytes has been defined. Peptide fragments formed by cleavage at arginine, glutamic acid, and methionine residues were analyzed by Edman degradation or digestion with carboxypeptidase. The complete primary structure of human hypoxanthine-guanine phosphoribosyltransferase was established by sequence analysis of 17 peptide fragments, 15 of which were purified by reverse-phase high pressure liquid chromatography. The enzyme is 217 residues long with a molecular weight equal to 24,470. Mass spectroscopy indicated that the NH2-terminal alanine is acetylated.

Amino Acid Sequence↗
PubMed1982

Isolation of denatured proteins and peptides by high-performance liquid chromatography. Effect of different perfluorinated acids, column length and large-pore supports.

The utilization of high-performance liquid chromatography for the isolation of peptides and proteins is extended by the demonstration that trifluoroacetic acid, pentafluoropropionic acid and heptafluorobutyric acid are effective peptide and protein solvents and as components of a mobile phase alter both the absolute and relative retention times of eluting peptides. In addition, studies related to stationary-phase performance indicate that: (1) column length (5-25 cm) does not significantly influence large peptide or protein retention times or resolution; (2) 300 A pore supports are ideal for the isolation of both large peptides and proteins; (3) peptide and protein conformation, even in the presence of denaturants, alters the steric interaction with the support; and (4) large peptides and proteins probably interact with the support by virtue of multi-site binding, not partitioning between the stationary and mobile phases.

Chromatography, High Pressure Liquid↗
PubMed1982

Relationship of the structure and biological activity of the natural homologues of tunicamycin.

The antibiotic tunicamycin was separated into 16 different components using reversed-phase high performance liquid chromatography. The effect of the eight major tunicamycin homologues on protein glycosylation and protein biosynthesis was examined. All homologues tested inhibited lipid-mediated protein glycosylation in chick or mouse fibroblasts. These homologues also inhibited the transfer of N-acetylglucosamine-1-phosphate from UDP-N-acetylglucosamine to dolichyl phosphate in chick liver microsome preparations, whereas the transfer of mannose from GDP-mannose to the lipid acceptor was hardly affected. The inhibition of protein glycosylation in fibroblasts or in microsomal preparations was concentration-dependent and maximum inhibition occurred at different concentrations for different homologues. The eight homologues differed in their ability to cause inhibition of protein synthesis.

Animals↗
PubMed1982

Inhibition of protein glycosylation and selective cytotoxicity toward virally transformed fibroblasts caused by B3-tunicamycin.

The biological effect of B3-tunicamycin, the only known homologue of tunicamycin which contains a saturated fatty-acid side chain, was examined using chick embryo fibroblasts, a mouse fibroblastic line (3T3) and a virally transformed mouse fibroblastic line (SV40-3T3). This homologue inhibited the transfer of N-acetylglucosamine 1-phosphate from UDP-N-acetylglucosamine to dolichyl phosphate, catalyzed by microsomes from chick liver or from cultured mouse fibroblasts. B3-tunicamycin also inhibited the incorporation of mannose into glycoproteins synthesized by chick or mouse fibroblasts. Incorporation of the amino acids proline and tyrosine was inhibited by B3-tunicamycin to a lesser extent than the incorporation of mannose. The mannose incorporation into glycoproteins synthesized by virally transformed cells was inhibited by B3-tunicamycin to a higher degree than what was achieved in the nontransformed lines or in the chick primary fibroblasts. When the activity of B3-tunicamycin as an inhibitor of protein glycosylation was compared to other homologues of tunicamycin, it was found to be the most active. This homologue caused complete (more than 95%) inhibition of protein glycosylation at a concentration of 50 ng/ml in chick and in mouse fibroblasts and at a concentration of 10 ng/ml in transformed mouse fibroblasts. When the cytotoxic activities of tunicamycin homologues were examined on nontransformed and virally transformed 3T3 cells, it was found that B3-tunicamycin displayed the highest selective cytotoxicity toward the transformed cells. When transformed fibroblasts (10(5) cells/plate) were treated with B3-tunicamycin (100 ng/ml) for 48 h, complete cell death was observed. The viability and the proliferative activity of the nontransformed fibroblast were normal even when treated with concentrations up to 500 ng/ml of B3-tunicamycin. This suggests that B3-tunicamycin may be a suitable candidate for studies of tumor growth in animals.

Animals↗
PubMed1981

Structural prediction of sugar-binding proteins functional in chemotaxis and transport.

Comparisons of the D-galactose- and D-ribose-binding protein amino acid sequences and secondary structure predictions with the known primary and three-dimensional structure of L-arabinose-binding protein suggest that the three proteins have similar molecular structures. These studies also indicate an evolutionary relationship among the proteins. One region of striking homology between the galactose- and ribose-binding proteins suggests that this may be th protein-protein contact site for interaction with the membrane-bound chemotaxis receptor. The ligands and the geometry of the galactose binding site are also predicted.

Amino Acid Sequence↗
PubMed1981

The amino acid sequence of the D-galactose-binding protein from Escherichia coli B/r.

The complete primary structure of the Escherichia coli B/r galactose-binding protein was determined by the automated sequencing of fragments produced by cleavage with cyanogen bromide, o-iodosobenzoic acid, limited trypsin digestion, mild acid hydrolysis, and Staphylococcus aureus strain V8 protease. The protein, which has 309 amino acids, is notable in the extent to which it differs from the L-arabinose-binding protein. Comparison of these two proteins indicates only about 18% homology despite the close structural resemblence of the molecules which they bind. The galactose-binding protein is the chemoreceptor initiating chemotaxis toward galactose, and it thus becomes the first protein component required for chemotaxis for which the primary structure is known. GM 24602

Amino Acid Sequence↗
PubMed1981

Reversed-phase supports for th resolution of large denatured protein fragments.

Large pore (much greater than 300 A), spherical partical silica stationary phases possessing either C18 or C8 hydrocarbon ligands out-performed small pore (60-100A), irregular shaped silicas for the purification of large denatured peptides. Since columns 5 cm in length appeared to be as effective in separating peptides as columns 5 times longer, it is likely that large peptides absorb to the matrix rather than partition between the stationary and mobile phases.

Chromatography, High Pressure Liquid↗
PubMed1981

Fragmentation of proteins with o-iodosobenzoic acid: chemical mechanism and identification of o-iodoxybenzoic acid as a reactive contaminant that modifies tyrosyl residues.

o-Iodoxybenzoic acid, a disproportionation product of o-iodosobenzoic acid, has been identified as a contaminant in most preparations of o-iodosobenzoic acid capable of both modifying and cleaving certain tyrosyl residues. A new synthetic approach for the production of o-iodosobenzoic acid containing low amounts of o-iodoxybenzoic acid combined with preincubation of the reagent with p-cresol to destroy the remaining o-iodoxybenzoic acid prior to the reaction with a polypeptide allows preparation of reagent solutions in which tyrosyl residues remain intact during tryptophanyl bond cleavage. In addition, the product produced by the action of o-iodosobenzoic acid upon tryptophanyl bonds has been identified as N-acyldioxindolylalanine. It is inferred from that structure that the chemical reaction proceeds via a two-step oxidation of the tryptophanyl residue followed by formation of an iminospirolactone which hydrolyzes, cleaving the peptide chain. Small peptides ending with dioxindolylalanine can be coupled to aminopropyl glass in high yield and are suitable for solid-phase Edman degradation.

Amino Acids↗
PubMed1980

Separation of large denatured peptides by reverse phase high performance liquid chromatography. Trifluoroacetic acid as a peptide solvent.

A method employing reverse phase high performance liquid chromatography has been developed for the purification of large denatured peptides. The cyanogen bromide fragments of hemoglobin alpha, beta, and gamma chains (13 to 91 residues in length) could be separated and recovered in 71 to 95% yields using LiChrosorb C-8 columns and a binary solvent system consisting of 0.013 M trifluoroacetic acid in water and a limiting organic solvent. This procedure permits the nondestructive detection of peptides at low wavelength (210 nm) on as little as 50 ng of sample. The peptides are recovered directly by evaporation or lyophilization. An elutropic solvent series for the separation of large and small peptides on reverse phase supports is also described.

Amino Acids↗
PubMed1980

Fetal hemoglobin of the rhesus monkey, Macaca mulatta: complete primary structure of the gamma chain.

The complete amino acid sequence of the gamma chain from the major one of two fetal hemoglobins from the rhesus monkey, Macaca mulatta, was determined by automated, stepwise degradation of selected fragments produced by cleavage at methionyl and tryptophanyl residues and at the single aspartylprolyl bond. The minor fetal hemoglobin is single aspartylprolyl bond. The minor fetal hemoglobin is similar to human Hb F1 in relative electrophoretic and chromatographic properties and in the level at which it is found (about 12% of the total Hb F). On these grounds, we assume that this minor component contains, like Hb FI, gamma chains that differ from those of the major component by virtue of acetylation of their amino-terminal glycyl residues. Although the gamma chains of most antropoid primates examined to date are structurally heterogeneous and, hence, appear to be encoded by nonallelic genes, no sign of structural heterogeneity was detected at any position in the major gamma chain from M. mulatta. Thus, if nonallelic gamma-chain genes exist in this species, the chains encoded by them may be identical in sequence. The gamma chain from M. mulatta is but the sixth primate gamma chain whose primary structure has been fully characteerized. The slight extent of structural divergence among these chains (the four chains from various species of Old World monkeys differ from one another by no more than two substitutions, while the human and cercopithecoid gamma chains differ at no more than five sites) attests to the conservative nature of gamma-chain evolution among the higher primates.

Amino Acid Sequence↗