| 2565345 |
The human platelet alloantigens, PlA1 and PlA2, are associated with a leucine33/proline33 amino acid polymorphism in membrane glycoprotein IIIa, and are distinguishable by DNA typing |
10.1172/JCI114082. |
J Clin Invest |
The human platelet alloantigens, PlA1 and PlA2, are associated with a leucine33/proline33 amino acid polymorphism in membrane glycoprotein IIIa, and are distinguishable by DNA typing
Abstract
- The human platelet alloantigens, PlA1 and PlA2, comprise a diallelic antigen system located on a component of the platelet fibrinogen receptor, membrane glycoprotein (GP) IIIa. Of the known platelet alloantigens, PlA1, which is carried by 98% of the caucasian population, appears to be the alloantigen that most often provokes neonatal alloimmune thrombocytopenic purpura and posttransfusion purpura. The structural features of the GPIIIa molecule responsible for its antigenicity are as yet unknown. Using the polymerase chain reaction (PcR), we amplified the NH2-terminal region of platelet GPIIIa mRNA derived from PlA1 and PlA2 homozygous individuals. Nucleotide sequence analysis of selected amplified cDNA products revealed a C in equilibrium T polymorphism at base 196 that created a unique Nci I restriction enzyme cleavage site in the PlA2, but not the PlA1 form of GPIIIa cDNA. Subsequent restriction enzyme analysis of cDNAs generated by PcR from 10 PlA1/A1, 5 PlA2/A2, and 3 PlA1/A2 individuals showed that Nci I digestion permitted clear discrimination between the PlA1 and PlA2 alleles of GPIIIa. All PlA2/A2 individuals studied contain a C at base 196, whereas PlA1 homozygotes have a T at this position. This single base change results in a leucine/proline polymorphism at amino acid 33 from the NH2-terminus, and is likely to impart significant differences in the secondary structures of these two allelic forms of the GPIIIa molecule. The ability to perform DNA-typing analysis for PlA phenotype may have a number of useful clinical applications, including fetal testing and determination of the phenotype of severely thrombocytopenic individuals.
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| 2566545 |
Molecular and clinical characterization of an insertional polymorphism of the insulin-receptor gene. |
10.2337/diab.38.6.737 |
Diabetes |
Molecular and clinical characterization of an insertional polymorphism of the insulin-receptor gene.
Abstract
- A restriction-fragment-length polymorphism (RFLP) detected with the human insulin-receptor cDNA and the enzyme Sac I has been reported to be associated with non-insulin-dependent diabetes mellitus (NIDDM) in White and Black populations and segregated with diabetes in two small pedigrees with maturity-onset diabetes of the young. A size difference of approximately 500 base pairs (bp) was demonstrated between the alleles of this and several other RFLPs that mapped to the same 300-bp region near the transmembrane coding region of the cDNA beta-chain, thus suggesting the presence of an insertion in this region that could affect insulin-receptor function. Genomic DNA fragments containing this RFLP were cloned from an individual heterozygous for the putative insertion, and the differing fragments of the two alleles were sequenced. The presence of a 400-bp insertion was thus confirmed and was demonstrated to be entirely within an intron. No significant coding-region differences from published cDNA sequences were detected in four exons sequenced from the region of the insertional allele. The sequenced regions included multiple Alu repeat sequences. The RFLP was unusual in that the larger allele consisted of an additional Alu repeat sequence that included a new Pst I site. Because the nature and location of the insertion did not suggest a role in insulin-receptor function, the association of this RFLP with NIDDM and hyperinsulinemia was reexamined in a small sample of Whites. No association could be demonstrated, and the insertion also failed to segregate with NIDDM in five White pedigrees.(ABSTRACT TRUNCATED AT 250 WORDS)
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| 2569533 |
Differential effects of somatostatin on atrial and ventricular contractile responses in guinea pig heart: influence of pretreatment with islet-activating protein |
None |
J Pharmacol Exp Ther |
Differential effects of somatostatin on atrial and ventricular contractile responses in guinea pig heart: influence of pretreatment with islet-activating protein
Abstract
- The effects of somatostatin on the contractile response of guinea pig cardiac preparations were investigated and compared with those of carbachol and adenosine. Somatostatin produced a concentration-dependent negative inotropic effect in the left atria, which was accompanied by a decrease in action potential duration. The maximum decrease in contractility which was obtained at 3 x 10(-6) M was around 40% of the predrug control values and far less than those produced by carbachol and adenosine. Somatostatin failed to produce inotropic effect on the papillary muscle and did not influence the spontaneously beating rate of the right atria. In the papillary muscles, however, somatostatin inhibited the positive inotropic effect of isoproterenol in a concentration-dependent manner as did carbachol and adenosine. In addition, somatostatin caused a significant inhibition of the isoproterenol-induced increase in cyclic AMP levels without affecting the basal level of cyclic AMP. In the papillary muscle, the inhibitory effect of somatostatin on the positive inotropic response to isoproterenol was significantly attenuated by pretreatment with islet-activating protein, and was significantly antagonized by the somatostatin antagonist cyclo7-aminoheptanoyl-Phe-D-Trp-Lys-Thr(Bzl). These results suggest that somatostatin receptors in guinea pig ventricular muscles are coupled with adenylate cyclase via islet-activating protein-sensitive GTP-binding protein, whereas the negative inotropic effect of somatostatin in the left atria might be mediated by a subtype of somatostatin receptors which is different from that in the ventricle.
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| 2569967 |
Human atrial natriuretic peptide receptor defines a new paradigm for second messenger signal transduction. |
10.1002/j.1460-2075.1989.tb03518.x |
EMBO J. |
Human atrial natriuretic peptide receptor defines a new paradigm for second messenger signal transduction.
Abstract
- We isolated cDNAs encoding a 115 kd human atrial natriuretic peptide (alpha ANP) receptor (ANP-A receptor) that possesses guanylate cyclase activity, by low-stringency hybridization with sea urchin Arbacia punctulata membrane guanylate cyclase probes. The human ANP-A receptor has a 32 residue signal sequence followed by a 441 residue extracellular domain homologous to the 60 kd ANP-C receptor. A 21 residue transmembrane domain precedes a 568 residue cytoplasmic domain with homology to the protein kinase family and to a subunit of the soluble guanylate cyclase. COS-7 cells transfected with an ANP-A receptor expression vector displayed specific [125I]alpha ANP binding, and exhibited alpha ANP stimulated cGMP production. These data demonstrate a new paradigm of cellular signal transduction where extracellular ligand binding allosterically regulates cyclic nucleotide second-messenger production by a receptor cytoplasmic catalytic domain.
|
| 2581245 |
Nucleotide sequence of cDNA encoding human alpha 2-macroglobulin and assignment of the chromosomal locus. |
10.1073/pnas.82.8.2282 |
Proc. Natl. Acad. Sci. U.S.A. |
Nucleotide sequence of cDNA encoding human alpha 2-macroglobulin and assignment of the chromosomal locus.
Abstract
- Six alpha 2-macroglobulin (alpha 2M) cDNA clones were isolated from a human liver cDNA library by using synthetic oligonucleotides as hybridization probes. One of these, p alpha 2M1, carries a 4.6 kilobase-pair insert, which was sequenced. The insert contains the coding sequences for the mature alpha 2M polypeptide (1451 amino acids) and for a 23-amino acid signal peptide at the NH2 terminus of the precursor pro-alpha 2M. At the 3' end of the insert a poly(A) addition signal A-A-T-A-A-A and part of the poly(A) tail of the messenger RNA were found. The protein sequence deduced from the nucleotide sequence agrees with the published alpha 2M amino acid sequence for all except three residues. The alpha 2M locus was assigned to human chromosome 12 by Southern blot analysis with DNA from a panel of mouse/human somatic cell hybrids, using alpha 2M cDNA as a hybridization probe.
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| 2583108 |
The refined 1.9 A crystal structure of human alpha-thrombin: interaction with D-Phe-Pro-Arg chloromethylketone and significance of the Tyr-Pro-Pro-Trp insertion segment |
10.1002/j.1460-2075.1989.tb08511.x. |
EMBO J |
The refined 1.9 A crystal structure of human alpha-thrombin: interaction with D-Phe-Pro-Arg chloromethylketone and significance of the Tyr-Pro-Pro-Trp insertion segment
Abstract
- A stoichiometric complex formed between human alpha-thrombin and D-Phe-Pro-Arg chloromethylketone was crystallized in an orthorhombic crystal form. Orientation and position of a starting model derived from homologous modelling were determined by Patterson search methods. The thrombin model was completed in a cyclic modelling-crystallographic refinement procedure to a final R-value of 0.171 for X-ray data to 1.92 A. The structure is in full agreement with published cDNA sequence data. The A-chain, ordered only in its central part, is positioned along the molecular surface opposite to the active site. The B-chain exhibits the characteristic polypeptide fold of trypsin-like proteinases. Several extended insertions form, however, large protuberances; most important for interaction with macromolecular substrates is the characteristic thrombin loop around Tyr60A-Pro60B-Pro60C-Trp60D (chymotrypsinogen numbering) and the enlarged loop around the unique Trp148. The former considerably restricts the active site cleft and seems likely to be responsible for poor binding of most natural proteinase inhibitors to thrombin. The exceptional specificity of D-Phe-Pro-Arg chloromethylketone can be explained by a hydrophobic cage formed by Ile174, Trp215, Leu99, His57, Tyr60A and Trp60D. The narrow active site cleft, with a more polar base and hydrophobic rims, extends towards the arginine-rich surface of loop Lys70-Glu80 that probably represents part of the anionic binding region for hirudin and fibrinogen.
|
| 2598466 |
Immunoreactive anionic and cationic trypsin in human serum |
10.1016/0009-8981(89)90254-4. |
Clin Chim Acta |
Immunoreactive anionic and cationic trypsin in human serum
Abstract
- A simple method for the purification of anionic and cationic trypsinogen and trypsin from human pancreatic juice applying affinity chromatography on aprotinin coupled Sepharose is described together with the N-terminal amino acid sequences for both trypsinogens. In addition, enzyme-linked immunoabsorbent assay (ELISA) methods for the determination of anionic and cationic trypsin-like immunoreactivity (irAT and irCT) are described. Normal serum levels are 21.3 +/- 7.4 micrograms/l and 27.8 +/- 9.0 microgram/l for irAT and irCT respectively and the accuracy of these assays is 6-10%. In our population, the normal ratio between irCT and irAT in serum is 1.36 +/- 0.42. In normal serum trypsin-like immunoreactivity consists solely of trypsinogen. In acute pancreatitis there is an increase over normal of both irAT and irCT with a proportionally greater increase in irAT than irCT. Similar changes are also found in uremic patients.
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| 2599760 |
Structure-toxicity relationships in the amatoxin series. Synthesis of S-deoxygamma(R)-hydroxy-Ile3-amaninamide, its crystal and molecular structure and inhibitory efficiency |
10.1111/j.1399-3011.1989.tb00234.x. |
Int J Pept Protein Res |
Structure-toxicity relationships in the amatoxin series. Synthesis of S-deoxygamma(R)-hydroxy-Ile3-amaninamide, its crystal and molecular structure and inhibitory efficiency
Abstract
- The amatoxins, highly toxic components of Amanita mushrooms, strongly inhibit the DNA-dependent RNA polymerase II (or B) in eukaryotic cell nuclei. For optimal binding to the enzyme a gamma-hydroxyisoleucine side chain in the 3-position is important as in gamma-amanitin (compound 1), where the OH-group is bound in the S-configuration. Amanullin, a non-toxic component, having an oxygen-free isoleucine side chain no. 3, exhibits an inhibitory effect on RNA polymerase II about two orders of magnitude smaller than that of gamma-amanitin. An equal, relatively weak, inhibitory effect has previously been found with the synthetically obtained Ile3-analog 7. In the present paper the synthesis of an analog (2) bearing a gamma-hydroxyl group in the isoleucine side chain is described. The compound was found to have about the same inhibitory effect on RNA polymerase II from Drosophila embryos as amanullin and the Ile3-analog 7. Structure analysis by X-ray diffraction revealed that the hydroxyl group at the -carbon atom of side chain-3 has the R-configuration, the new analog thus being -deoxo( )-hydroxy-Ile3-amaninamide. It follows that the S-configuration of this chiral center is a prerequisite to maximal toxicity. Crystallographic data demonstrating great similarity between the peptide backbones of the new analog and those of natural amatoxins are given.
|
| 2599769 |
17O, 14N and 15N n.m.r. studies of the Co2+ complexes of cyclo(Pro17O-Gly15N) and cyclo(Gly17O-Pro) in aqueous solution |
10.1111/j.1399-3011.1989.tb01578.x. |
Int J Pept Protein Res |
17O, 14N and 15N n.m.r. studies of the Co2+ complexes of cyclo(Pro17O-Gly15N) and cyclo(Gly17O-Pro) in aqueous solution
Abstract
- The complexation of cyclo(Pro17O-Gly15N) and cyclo(Gly17O-Pro) with Co2+ ions has been studied by 17O, 14N and 15N n.m.r. spectroscopy in aqueous solution. 17O, 14N and 15N transverse relaxation times and chemical shifts were measured as a function of temperature. The 17O n.m.r. studies unequivocally demonstrate that the cobaltous ion binds to the peptide oxygen of both compounds. The hyperfine coupling constant and the peptide residence times were found to be A = -0.165 MHz and -0.145 MHz, tau m = 16, and 92 microseconds for cyclo(Pro17O-Gly15N) and cyclo(Gly17O-Pro), respectively. The 14N and 15N studies of labeled cyclo(Pro17O-Gly15N) do not indicate binding at either the Gly15N or the Pro14N site.
|
| 2604750 |
Mechanistic aspects of the cytocidal action of ulithiacyclamide on mouse leukemia L1210 cells in vitro |
10.1016/0006-2952(89)90662-x. |
Biochem Pharmacol |
Mechanistic aspects of the cytocidal action of ulithiacyclamide on mouse leukemia L1210 cells in vitro
Abstract
|
| 2613788 |
Preparative reversed-phase high-performance liquid chromatography in the synthesis of viscosin, a cyclic depsipeptide |
10.1016/s0021-9673(01)88976-7. |
J Chromatogr |
Preparative reversed-phase high-performance liquid chromatography in the synthesis of viscosin, a cyclic depsipeptide
Abstract
- The importance of peptides in biochemical research and the facility with which they can be prepared by solid-phase techniques highlights the need for continuing research in the chromatographic purification of these molecules on a preparative scale. In this regard, synthesis of the cyclic depsipeptide antibiotic, viscosin, has provided the opportunity to demonstrate the use of radial compression cartridge technology in the reversed-phase purification of three key peptide intermediates on a scale of several hundred milligrams. Superior resolution of linear and cyclic peptide mixtures on a Bondapak C18 radial compression cartridge by using an aqueous acetonitrile solvent system containing 0.1% trifluoroacetic acid contributed significantly to the first total synthesis of viscosin, and demonstrates the applicability of this system to the purification of peptide mixtures.
|
| 2627300 |
7-Azido-actinomycin D: a photoaffinity probe of the sequence specificity of DNA binding by actinomycin D |
10.1080/07391102.1989.10508509. |
J Biomol Struct Dyn |
7-Azido-actinomycin D: a photoaffinity probe of the sequence specificity of DNA binding by actinomycin D
Abstract
- Actinomycin D (ActD) is a DNA-binding antitumor antibiotic that appears to act in vivo by inhibiting RNA polymerase. The mechanism of DNA binding of ActD has attracted much attention because of its strong preference for 5'-dGpdC-3' sequences. Binding is thought to involve intercalation of the tricyclic aromatic phenoxazone ring into a GC step, with the two equivalent cyclic pentapeptide lactone substituents lying in the minor groove and making hydrogen bond contacts with the 2-amino groups of the nearest neighbor guanines. Recent studies have indicated, however, that binding is also influenced by next-nearest neighboring bases. We have examined this higher order specificity using 7-azido-actinomycin-D as a photoaffinity probe, and DNA sequencing techniques to quantitatively monitor sites of covalent photoaddition. We found that GC doublets were strongly preferred only if the 5'-flanking base was a pyrimidine and the 3'-flanking base was not cytosine. In addition we observed a previously unreported preference for binding at a GG doublet in the sequence 5'-TGGG-3'."
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| 2635693 |
Structure and conformation of peptides containing the sulfonamide junction. II. Synthesis and conformation of cyclo-MeTau-Phe-DPro- |
10.1111/j.1399-3011.1989.tb01396.x. |
Int J Pept Protein Res |
Structure and conformation of peptides containing the sulfonamide junction. II. Synthesis and conformation of cyclo-MeTau-Phe-DPro-
Abstract
- By applying the method of amino-acyl incorporation to sulfonamido peptides, cyclo(-MeTau-Phe-DPro-) 3 has been synthesized in high yield starting from Z-MeTau-Phe-Pro-OH. The crystal structure and the molecular conformation of 3 have been determined. Crystals are orthorhombic, s.g. P2(1)2(1)2(1), with a = 5.454, b = 13.486, c = 24.025 A. The structure has been solved by direct methods and refined to R = 0.039 for 1974 reflections with I greater than 1.5 sigma (I). The 10-measured cyclopeptide adopts a backbone conformation in the crystals characterized by Phe-DPro and DPro-MeTau peptide bonds in trans and cis conformation, respectively. Both the peptide bonds deviate significantly from planarity and the corresponding delta omega values are ca. 12 degrees. The sulfonamide SO2NH junction adopts a cisoidal conformation with a C alpha 1-S1-N2-C alpha 2 torsion angle of 70.8 degrees. 13C n.m.r. data show that the trans geometry at the Phe-DPro junction found in the crystals is retained in DMSO solution. The 10-membered ring of 3 is characterized by a pseudo mirror-plane passing through the Phe nitrogen and the DPro carbonylic carbon. The DPro ring adopts a half-chair conformation. The Phe side chain conformation corresponds to the statistically most favored g- rotamer (chi 1 = -68.6 degrees). The crystal packing is characterized by a weak intermolecular hydrogen bond between NH group and the MeTau O1' oxygen."
|
| 2663128 |
Bactericidal action of peptide antibiotic AS-48 against Escherichia coli K-12 |
10.1139/m89-048. |
Can J Microbiol |
Bactericidal action of peptide antibiotic AS-48 against Escherichia coli K-12
Abstract
- Peptide antibiotic AS-48 exerts a bactericidal mode of action on exponential cultures of Escherichia coli K-12 through a multi-hit kinetics interaction. AS-48 causes a parallel and gradual cessation of all biosynthetic pathways monitored (protein, RNA, DNA, and cell wall synthesis), the rate of incorporation of labeled precursors, the rate of O2 consumption, and cell growth. These effects have been attributed to alterations of cytoplasmic membrane functions.
|
| 2667998 |
Iron metabolism of Escherichia coli studied by Mössbauer spectroscopy and biochemical methods |
10.1111/j.1432-1033.1989.tb14938.x. |
Eur J Biochem |
Iron metabolism of Escherichia coli studied by Mössbauer spectroscopy and biochemical methods
Abstract
- To date it has barely been recognized that the nature of about 75% of the Escherichia coli iron pool is unknown. Here we report the isolation of two iron species representing major components of iron metabolism in various growth states of E. coli. In vivo Mössbauer spectroscopy was applied to obtain information on the intracellular distribution pattern of iron in E. coli K12 W3110. Only two types of iron could be detected in the cell spectra: hexacoordinated Fe2+ and Fe3+ high-spin complexes. Other iron-requiring compounds are at least one order of magnitude less abundant in E. coli. The Mössbauer parameters of these complexes fit neither cytochromes nor iron-sulfur proteins nor ferric holo-bacterioferritin. They are sensitive to metabolic changes and inhibitors. The ratio of Fe/subunit, Fe2+/Fe3+ interconversion, chromatographic and electrophoretic data exclude bacterioferritin as the main iron metabolite in E. coli. Bacterioferritin can be observed only at very high ferric ion concentrations in the medium. The 55Fe fluorograms of both cytoplasmic and membrane fractions exhibit two exclusive bands with apparent molecular masses of 17 and 15 kDa, respectively. The two bands comprised 70% of the applied radioactivity. In gel filtration the main iron peak elutes at 155 kDa yielding two bands with apparent molecular masses of 17 and 15 kDa on SDS/PAGE. We therefore conclude that the iron species form a protein with an apparent molecular mass of 155 kDa containing 17-kDa and 15-kDa subunits. The iron content of the protein is 44 micrograms Fe/mg protein which corresponds to approximately 13 iron ions/subunit. No iron protein exhibiting the observed features has been described so far. Additional Mössbauer experiments suggest that these novel iron proteins are not restricted to E. coli but that similar components are detectable in several bacterial and fungal systems, thus pointing to a general occurrence.
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