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C A Slaughter

Publications and source records attributed to C A Slaughter.

At least 109 records · Page 6Linked to original sources
PubMed1988

Sites phosphorylated in myosin light chain in contracting smooth muscle.

Purified smooth muscle myosin light chain can be phosphorylated at multiple sites by myosin light chain kinase and protein kinase C. We have determined the sites phosphorylated on myosin light chain in intact bovine tracheal smooth muscle. Stimulation with 10 microM carbachol resulted in 66 +/- 5% monophosphorylated and 11 +/- 2% diphosphorylated myosin light chain after 1 min, and 47 +/- 4% monophosphorylated and 5 +/- 2% diphosphorylated myosin light chain after 30 min. Myosin heavy chain contained 0.06 +/- 0.01 mol of phosphate/mol of protein which did not change with carbachol. At both 1 and 30 min the monophosphorylated myosin light chain contained only phosphoserine whereas the diphosphorylated myosin light chain contained both phosphoserine and phosphothreonine. Two-dimensional peptide mapping of tryptic digests of monophosphorylated and diphosphorylated myosin light chain obtained from carbachol-stimulated tissue was similar to the peptide maps of purified light chain monophosphorylated and diphosphorylated, respectively, by myosin light chain kinase; these maps were distinct from the map obtained with tracheal light chain phosphorylated by protein kinase C. Phosphorylation of tracheal smooth muscle myosin light chain by myosin light chain kinase yields the tryptic phosphopeptide ATSNVFAMFDQSQIQEFK with S the phosphoserine in the monophosphorylated myosin light chain and TS the phosphotreonine and phosphoserine in the diphosphorylated myosin light chain. Thus, stimulation of tracheal smooth muscle with a high concentration of carbachol results in formation of both monophosphorylated and diphosphorylated myosin light chain although the amount of diphosphorylated light chain is substantially less than monophosphorylated light chain. In the intact muscle, myosin light chain is phosphorylated at sites corresponding to myosin light chain kinase phosphorylation.

Animals↗
PubMed1988

Analysis of phenylthiohydantoin amino acid mixtures for sequencing by thermospray liquid chromatography/mass spectrometry.

Phenylthiohydantoin (PTH) amino acids, the derivatives of amino acids liberated in the course of automated N-terminal sequence analysis of peptides and proteins, are most commonly identified by high-performance liquid chromatography. This communication describes an extension to the methodology for PTH amino acid identification which exploits thermospray liquid chromatography/mass spectrometry for use in the confirmation of PTH amino acid identifications previously made solely on the basis of retention times. Thermospray mass spectra of the 19 synthetic PTH amino acids corresponding to the residues commonly observed during N-terminal sequencing have been acquired. These spectra show strong signals for the protonated molecular ion, accompanied in several cases by ions produced by limited fragmentation of the amino acid side chain and/or the PTH ring system. A reverse-phase separation protocol has been adapted for use with thermospray. The method permits recognition of the protonated molecular ions of all the standard PTH amino acids at the 150-pmol level on the basis of signal-to-noise ratios of 10:1 or better with full scanning. The method has been tested on the N-terminal amino acid sequence analysis of 200 pmol of the standard protein beta-lactoglobulin A, and has been found useful in the study of selected side-products of the sequencing chemistry.

Amino Acid Sequence↗
PubMed1988

The structure of cytochrome b561, a secretory vesicle-specific electron transport protein.

Cytochrome b561 is a transmembrane electron transport protein that is specific to a subset of secretory vesicles containing catecholamines and amidated peptides. This protein is thought to supply reducing equivalents to the intravesicular enzymes dopamine-beta-hydroxylase and alpha-peptide amidase. We have purified cytochrome b561 from bovine adrenal chromaffin granules by reverse phase chromatography and have determined internal amino acid sequences from peptides. Complementary oligonucleotides were used to isolate two cDNA clones from a bovine brain library. The structure predicted by the sequences of these cDNAs suggests a highly hydrophobic protein of 273 amino acids which spans the membrane six times with little extramembranous sequence. Cytochrome b561 is not homologous to any other cytochrome and thus represents a new class of electron carriers. RNA blotting experiments indicate that cytochrome b561 is expressed in the adrenal medulla and all brain regions of the cow, but not in visceral organs. This result agrees well with the putative function of this unique cytochrome and with the notion that this protein is localized to large dense-core synaptic vesicles.

Amino Acid Sequence↗
PubMed1988

Multiple genes encode nuclear factor 1-like proteins that bind to the promoter for 3-hydroxy-3-methylglutaryl-coenzyme A reductase.

DNA-binding proteins of the nuclear factor 1 (NF1) family recognize sequences containing TGG. Two of these proteins, termed reductase promoter factor (RPF) proteins A and B, bind to the promoter for hamster 3-hydroxy-3-methylglutaryl-coenzyme A reductase, a negatively regulated enzyme in cholesterol biosynthesis. In the current study, we determined the sequences of peptides derived from hamster RPF proteins A and B and used this information to isolate a cDNA, designated pNF1/Red1, that encodes RPF protein B. The peptide sequence of RPF protein A, the other reductase-related protein, suggests that it is the hamster equivalent of NF1/L, which was previously cloned from rat liver. We also isolated a hamster cDNA for an additional member of the NF1 family, designated NF1/X. Thus, the hamster genome contains at least three genes for NF1-like proteins. It is likely to contain a fourth gene, corresponding to NF1/CTF, which was previously cloned from the human. The NH2-terminal sequences of all four NF1-like proteins (NF1/Red1, NF1/L, NF1/X, and NF1/CTF), which are virtually identical, contain the DNA-binding domain that recognizes TGG. Functional diversity may arise from differences in the COOH-terminal sequences. We hypothesize that the COOH-terminal domain interacts with adjacent DNA-binding proteins, thereby stabilizing the binding of a particular NF1-like protein to a particular promoter. This protein-protein interaction confers specificity to a class of proteins whose DNA-recognition sequence is widespread in the genome. Sterols may repress transcription of the reductase gene by disrupting this protein-protein interaction.

Amino Acid Sequence↗
PubMed1988

Human 67-kDa calelectrin contains a duplication of four repeats found in 35-kDa lipocortins.

The 67-kDa calelectrin is the largest member of a family of Ca2+-binding proteins that associate with membranes and phospholipids in a Ca2+-dependent manner. Oligonucleotide probes based on peptide sequences obtained from purified bovine 67-kDa calelectrin were used to screen a human retina cDNA library, and the complete primary structure of human 67-kDa calelectrin was deduced by DNA sequence analysis. The protein consists of eight 68-amino acid repeats separated by linking sequences of variable lengths. It is highly similar to the human lipocortin I and II sequences, each of which contains four such repeats. The amino termini of the three proteins show no sequence similarity; however, in the repeated regions the proteins are 42-45% identical in sequence. Analysis of the 16 repeats from the three proteins provides insights into the structural basis for Ca2+-dependent phospholipid binding. These data place the calelectrins and the lipocortins into the same gene family and suggest that these proteins have similar functions and have evolved from a common ancestor.

Amino Acid Sequence↗
PubMed1987

Phosphorylation of serine 833 in cytoplasmic domain of low density lipoprotein receptor by a high molecular weight enzyme resembling casein kinase II.

A soluble protein kinase that phosphorylates the last serine residue (Ser-833) in the cytoplasmic domain of the low density lipoprotein (LDL) receptor was purified about 1300-fold from the cytosol of bovine adrenal cortex. The LDL receptor kinase shared several properties with casein kinase II: use of either GTP or ATP; phosphorylation of a typical casein kinase II recognition sequence in the LDL receptor (a serine followed by a cluster of three negatively charged amino acids); and inhibition by heparin. The LDL receptor kinase differed from classic casein kinase II in the following respects: its apparent molecular weight on gel filtration was approximately 500,000 as opposed to the usual molecular weight of 130,000 for casein kinase II; its affinity for the LDL receptor (apparent Km approximately 5 nM) was much greater than its affinity for casein (approximately 10 microM); and its activity was inhibited by polylysine, an agent that stimulates casein kinase II. The physiologic role of this unusual kinase, if any, is unknown.

Adenosine Triphosphate↗
PubMed1986

Cytoplasmic 3-hydroxy-3-methylglutaryl coenzyme A synthase from the hamster. I. Isolation and sequencing of a full-length cDNA.

We here report the isolation and nucleotide sequencing of a full-length 3.3-kilobase cDNA for the cytoplasmic form of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) synthase, a regulated enzyme in the cholesterol biosynthetic pathway. The cDNA was isolated from UT-1 cells, a compactin-resistant line of Chinese hamster ovary cells. UT-1 cells produce large amounts of mRNA for HMG-CoA synthase and the next enzyme in the pathway, HMG-CoA reductase, as a result of growth in the presence of compactin, a competitive inhibitor of the reductase. The identity of the cDNA for HMG-CoA synthase was confirmed through comparison of the NH2-terminal amino acid sequence predicted from the cDNA with that determined chemically from the purified enzyme. Anti-peptide antibodies directed against the amino acid sequence predicted from the cDNA precipitated HMG-CoA synthase activity from liver cytoplasm. The feeding of cholesterol to hamsters led to a decrease of more than 85% in the amount of mRNA for HMG-CoA synthase and HMG-CoA reductase in hamster liver. These data indicate that the mRNAs for cytoplasmic HMG-CoA synthase and for HMG-CoA reductase, two sequential enzymes in the cholesterol biosynthetic pathway, are coordinately regulated by cholesterol.

Amino Acid Sequence↗
PubMed1984

Use of JH4 joining segment gene by an anti-arsonate antibody that bears the major A-strain cross-reactive idiotype but displays diminished antigen binding.

One of the antibody families utilized by the A/J mouse in its response to p-azophenylarsonate (Ars) is characterized by the expression of the major anti-arsonate cross-reactive idiotype (CRI) of the A strain. This family has been termed the Ars-A family. A hybridoma antibody (HP 101F11 ) obtained after immunization of an A/J mouse with Ars was identified initially as displaying the CRI, but was subsequently found to bind antigen at a level much lower than most members of the Ars-A family. The results of binding studies suggested that HP 101F11 possesses reduced avidity for antigen. When isolated light and heavy chains were allowed to recombine with the heavy and light chains of a strongly antigen-binding, strongly CRI-positive antibody of the Ars-A family (HP 93G7 ), the low level of antigen binding by HP 101F11 was found to be due to a structurally variant heavy chain. Whereas antibodies of the Ars-A family with normal avidity for antigen had been shown to use the JH2 joining segment gene, amino acid sequence analysis of HP 101F11 revealed that this antibody has a JH segment with a sequence identical to that encoded by a portion of a different JH gene, JH4 . The implication that 101F11 uses the JH4 gene instead of JH2 was supported by the observation that the productively rearranged gene is associated with an Eco R1 restriction fragment 0.95 Kb smaller than the corresponding fragments of Ars-A hybridomas with normal avidity for antigen. The size difference of 0.95 Kb corresponds exactly to the known distance between the JH2 and JH4 genes in BALB/c germline DNA. In addition to the structural differences immediately attributable to the use of JH4 , HP 101F11 has shown an amino acid interchange in the DH segment, and a single amino acid deletion at the DH-JH boundary. These results show that variation among members of the Ars-A family in the DH and/or JH segments provides alternative structural forms of Ars-A antibodies upon which selective processes can operate during the course of an immune response.

Amino Acid Sequence↗
PubMed1983

Amino acid sequence diversity within the family of antibodies bearing the major antiarsonate cross-reactive idiotype of the A strain mouse.

VH region amino acid sequences are described for five A/J anti-p-azophenylarsonate (anti-Ars) hybridoma antibodies for which the VL region sequences have previously been determined, thus completing the V domain sequences of these molecules. These antibodies all belong to the family designated Ars-A which bears the major anti-arsonate cross-reactive idiotype (CRI) of the A strain mouse. However, they differ in the degree to which they express the CRI in standard competition radioimmunoassays. Although the sequences are closely related, all are different from each other. Replacements are distributed throughout the VH region and occur in positions of the chain encoded by all three gene segments, VH, DH, and JH. It is likely that somatic diversification processes play a dominant role in producing the sequence variability in each of these segments. The number of differences from the sequence encoded by the germline is smallest for antibodies that express the CRI most strongly, suggesting that somatic diversification is responsible for loss of the CRI in members of the Ars-A antibody family. There is an unusual degree of clustering of differences in both CDR2 and CDR3 and many of the substitutions are located in "hot spots" of variation. The large number of differences between the chains prohibits the unambiguous identification of positions at which alterations play a major role in reducing the expression of the CRI. However, the data suggest that the loss of the CRI is associated with a definable repertoire of somatic changes at a restricted number of highly variable sites.

Amino Acid Sequence↗
PubMed1983

Amino acid sequence of the N-terminal domain of calf thymus histone H2A.Z.

The minor histone H2A subtype, H2A.Z, has been purified to homogeneity from calf thymus and subjected to automated Edman degradation. The sequence of the first 30 amino acids possesses only 60% homology with major H2A subtypes of the same tissue. This sequence difference is more extreme than that exhibited between evolutionarily distant major H2A subtypes. However, an analysis of secondary structure reveals that H2A.Z and major H2A subtypes exhibit the same general topographical features within their N-terminal domains.

Amino Acid Sequence↗
PubMed1983

Discrimination of human placental alkaline phosphatase allelic variants by monoclonal antibodies.

Eighteen monoclonal antibodies were produced by the mouse hybridoma method using purified placental alkaline phosphatase (ALP) as antigen. The ability of the various antibodies to discriminate among allelic variants of the enzyme was tested using a large panel of placental ALPs that had been typed electrophoretically. The panel included sets of samples of each of the six common polymorphic phenotypes as well as a series of rare variants. The reactivity of each antibody with each placental ALP (binding ratio) was determined relative to a single standard placental ALP (type 1) in a quantitative binding assay. The findings for six of the antibodies have already been reported. The results on the other 12 antibodies are presented here, and the combined data on the total series of 18 antibodies are analyzed and discussed. Six of the 18 antibodies showed significantly reduced binding to one or another of the products of the three common alleles. In three cases, the discrimination was reflected by essentially "all-or-none" binding reactions. In the other three cases, the binding differences were less marked but could be demonstrated by quantitative comparisons of the binding ratios. Quantitative binding ratio comparisons also enabled heterozygotes to be differentiated from homozygotes in each case. Some of the antibodies showed reduced binding with certain of the rare variant ALP electrophoretic phenotypes. It is estimated that at a minimum this unselected series of 18 antibodies is directed to at least nine different antigenic determinants on the surface of the placental ALP molecule. The results illustrate the power of monoclonal antibodies to discriminate among allelic variants of enzymes.

Alkaline Phosphatase↗
PubMed1982

A monoclonal antibody that reacts with nonallelic enzyme glycoproteins.

One of six monoclonal antibodies raised against purified human placental alkaline phosphatase cross-reacts with the adult and fetal forms of intestinal alkaline phosphatase. The placental and intestinal enzymes are nonallelic. A new electrophoretic titration procedure was used to assess the relative reactivities of the different enzymes with the antibody. The placental enzyme was the most reactive. However, the adult intestinal enzyme showed greater reactivity than the fetal enzyme. The determinants to which the antibody binds on these three forms of alkaline phosphatase presumably differ in their detailed molecular configurations.

Alkaline Phosphatase↗
PubMed1982

Monoclonal antibodies to immunoglobulin G4 induce histamine release from human basophils in vitro.

Monoclonal murine antibodies to human IgE, IgG1, IgG2, IgG3, IgG4, IgM, and IgA1 were prepared and their abilities to stimulate histamine release from human peripheral blood leukocytes were investigated. As expected, anti-IgE caused 8% to 76% histamine release from the leukocytes of each of 14 nonallergic donors. In one subject anti-IgE alone had no effect, but a 15% histamine release did occur after the subsequent addition of a goat anti-mouse IgG antiserum to crosslink cell-bound anti-IgE molecules. Anti-IgG4 alone caused 5% to 59% histamine release from the cells of four of 14 donors. Subsequent challenge with goat anti-mouse IgG caused an additional release of up to 15% of the basophil histamine, but only from leukocytes of donors responsive to anti-IgG4 alone. No histamine release was detected after stimulation by monoclonal antibodies to IgG1, IgG2, IgG3, IgM, or IgA1. The results of this study indicate that monoclonal antibodies to IgG4 as well as to IgE can stimulate human peripheral blood leukocytes to release histamine. These observations support the theory that antigen-IgG4 interactions can stimulate histamine release from human basophils.

Animals↗
PubMed1981

Detection of enzyme polymorphism by using monoclonal antibodies.

Six monoclonal antibodies against human placental alkaline phosphate [orthophosphoric-monoester phosphohydrolase (alkaline optimum), EC 3.1.3.1], a highly polymorphic enzyme, were tested for reactivity against a panel of 295 placental extracts that had been typed electrophoretically. The products of the three common alleles as well as several rare alleles could be discriminated by the various antibodies. In some cases differences between allelic products were reflected by essentially "all-or-none" reactions, but in other cases the differences were smaller and demonstrable only by quantitative analysis of the binding. Evidence for allelic differences not detectable electrophoretically was also obtained.

Alkaline Phosphatase↗
PubMed1981

Electrophoresis of enzyme--monoclonal antibody complexes: studies of human placental alkaline phosphatase polymorphism.

Enzyme--monoclonal antibody complexes formed between six different monoclonal antibodies and the six phenotypes of human placental alkaline phosphatase [orthophosphoric-monoester phosphohydrolase (alkaline optimum), EC 3.1.3.1] that represent the homozygous and heterozygous combinations of the three common alleles have been examined by electrophoresis in starch, acrylamide, and agarose gels. Since the complexes formed retain full enzyme activity, they could be detected after gel electrophoresis by an enzyme stain. Distinctive electrophoretic patterns were obtained with each monoclonal antibody. Differential binding of certain of the antibodies with the products of different alleles produces clear discrimination of various homozygous and heterozygous phenotypes. This discrimination parallels the results previously obtained by using a quantitative binding radioimmunoassay. The results show that this general method should prove useful in screening hybridoma fluids for the presence of monoclonal antibodies to specific enzymes; in the detection of allelic variation, even where this is not expressed by electrophoretic differences among the uncomplexed enzymes; and in discriminating between homozygotes and heterozygotes. It could also prove to be a useful tool in the elucidation of the molecular structures of enzyme--monoclonal antibody complexes.

Alkaline Phosphatase↗