Purification and structural characterization of the CD11b/CD18 integrin alpha subunit I domain reveals a folded conformation in solution.

The alpha subunits of the leukocyte CD11/CD18 integrins contain an approximately 200 amino acid 'inserted' or I domain. The I domain of the cell-surface Mac-1 (CD11b/CD18) integrin has been shown to be the major recognition site for several adhesion ligands, including iC3b, fibrinogen, factor X, and ICAM-1. The I domain from the Mac-1 alpha subunit has been expressed in Escherichia coli as a soluble GST-fusion protein containing a factor Xa sensitive cleavage site.

Application of thermally assisted electrospray ionization mass spectrometry for detection of noncovalent complexes of bovine serum albumin with growth hormone releasing factor and other biologically active peptides.

Ion-spray ionization mass spectrometry with gentle conditions for solvent removal has been reported as a useful tool for detection of high-affinity noncovalent complexes of biological relevance formed in solution. Two main objectives of this study were (i) to find whether other types of electrospray ionization (ESI) sources, e.g.

Utility of the parent-neutral loss scan screening technique: partial characterization of urinary metabolites of U-78875 in monkey urine.

Metabolites of an antianxiety-sedative drug candidate (U-78875; 3-(5-cyclopropyl-1,2,4-oxadiazol-3-yl)-5-(1-methylethyl)-imidazo[1 ,5-alpha] quinoxalin-4(5H)-one (I)) present in the urine of monkeys were detected using tandem mass spectrometry (MS/MS) by application of parent ion scans and characterized or partially characterized by performing daughter ion scans of the pseudo-molecular ions of suspected metabolites. The use of liquid secondary ion mass spectrometry ionization of crude urinary extracts in combination with tandem quadrupole MS/MS analyses using parent ion scans of m/z 69 and subsequent daughter ion scans characterized unmetabolized I and N-dealkyl I (U-85466) and partially characterized aryl hydroxyl, aryl hydroxyl-N-dealkyl, aryl O-glucuronide, aryl O-glucuronide-N-dealkyl, aryl O-sulfate and aryl O-sulfate-N-dealkyl metabolites. From these data it was concluded that some of the metabolic pathways involved in the biotransformation of U-78875 include N-dealkylation, aryl hydroxylation and conjugation of aryl hydroxides.

Capillary electrophoresis-electrospray mass spectrometry for the analysis of recombinant bovine and porcine somatotropins.

A Beckman P/ACE 2050 high-performance capillary electrophoresis (HPCE) instrument has been interfaced with a Vestec electrospray ionization (ESI) mass spectrometer for the analysis of recombinant proteins. Peak resolution is not compromised by coupling HPCE to an ESI mass spectrometer. Recombinant bovine and porcine somatotropins (rbSt and rpSt) were used as model proteins.

Purification of lincosaminide O-nucleotidyltransferase from Streptomyces coelicolor Müller.

An enzyme (lincosaminide O-nucleotidyltransferase) that catalyzes 3-(5'-ribonucleotidylation) of pirlimycin and several other lincosaminide antibodies has been purified approximately 35-fold from cell-free extracts of Streptomyces coelicolor Müller NRRL 3532 (UC 5240). The crude enzyme was prepared using lysozyme and was treated with MnCl2 and (NH4)2SO4. Final purification was achieved by anion exchange chromatography.

Naphtho and benzo analogues of the kappa opioid agonist trans-(+/-)-3,4-dichloro-N-methyl-N-[2-(1-pyrrolidinyl)cyclohexyl] benzeneacetamide.

Further elaboration on the structure-activity relationships in our U-50,488 series has revealed that benzologation of this cyclohexane-1,2-diamine derivative provides compounds which either maintain the interaction with the kappa receptor (e.g. compounds 3a and 5a in the phenylacetamido series) or eliminate the mu receptor mediated analgesia (e.

Particle beam liquid chromatography-mass spectrometry on a double-focusing sector instrument.

A commercially available particle beam interface developed by the Vestec Corporation has been coupled to a double-focusing high-resolution mass spectrometer (VG ZAB 2F) via a momentum separator. An ultraviolet detector was in-line with the interface and allowed monitoring of the eluting materials. With this instrumentation, complete electron-impact (EI) mass spectra on synthetic mixtures of steroids, nucleosides, and several derivatives of amino acids were recorded.

Electrospray mass spectrometry of recombinant growth hormones.

The electrospray mass spectra of several standard proteins were recorded and their molecular weights determined. These were compared to Literature values obtained by other laboratories. The agreement was quite good.

O-demethylpaulomycins A and B, U-77,802 and U-77,803, paulomenols A and B, new metabolites produced by Streptomyces paulus.

O-Demethylpaulomycin A (C33H44N2O17S), O-demethylpaulomycin B (C32H42N2O17S), paulomenol A (C29H43NO16), paulomenol B (C28H41NO16), and the hydrogen sulfide adducts of paulomycin A (U-77,802, C34H48N2O17S2), and paulomycin B (U-77,803, C33H46N2O17S2) have been isolated from fermentations of Streptomyces paulus strain 273. The structure of these compounds was determined by 1H and 13C NMR and fast atom bombardment mass spectrum spectroscopic techniques and degradative studies. The antibacterial properties of these new metabolites, which are related to paulomycins A and B (J.

Adenylylation of trospectomycin by crude enzyme preparations from Escherichia coli.

Employing osmotically shocked lysate of a spectinomycin resistant strain of Escherichia coli, trospectomycin, a new alkylspectinomycin, was adenylylated in the presence of adenosine 5'-triphosphate and magnesium ion. A highly resistant strain of E. coli was obtained by transforming a laboratory strain with a newly constructed plasmid consisting of pBR322 and a determinant for spectinomycin resistance originally found on a low copy number plasmid in E.

Structural relationships between senfolomycins and paulomycins.

Senfolomycins A and B (Antimicrob. Agents Chemother.-1965: 828-831, 1966) are two antibacterial agents with physico-chemical and biological properties similar to those of paulomycin.

New paulomycins produced by Streptomyces paulus.

Paulomycin A2 (C34H46N2O17S), paulomycin C (C32H42N2O17S), paulomycin D (C31H40N2O17S), paulomycin E (C29H36N2O16S) and paulomycin F (C29H38N2O16S) have been isolated from fermentations of Streptomyces paulus strain 273. The structure of these compounds was determined using NMR and mass spectroscopic techniques. The new paulomycins, like paulomycins A and B (J.

Purification and characterization of digitalislike factors from human plasma.

Increased levels of a humoral inhibitor of active sodium transport have been associated with the response to acute and chronic hypervolemia and various forms of experimental as well as human essential hypertension. In this report, we describe the purification of inhibitors of Na+, K+-adenosine triphosphatase (ATPase) from the plasma of volume-expanded individuals. Of the two amphipathic materials obtained, only one of the factors when present in high concentrations showed the slow time-dependent component of inactivation similar to that of the cardiac glycosides.

Arginomycin: production, isolation, characterization and structure.

Arginomycin is a new nucleoside antibiotic produced by Streptomyces arginesis. Arginomycin, C18H28N8O5, which inhibits the growth of Gram-positive bacteria and fungi in vitro, is structurally related to blasticidin S and found to be relatively non-toxic.

Paulomycin-related antibiotics: paldimycins and antibiotics 273a2. Isolation and characterization.

The isolation of paulomycins A and B from fermentations of Streptomyces paulus has been reported earlier [J. Antibiotics 35: 285-294, 1982]. Further work on the antibiotics produced by S.

Paldimycins A and B and antibiotics 273a2 alpha and 273a2 beta. Synthesis and characterization.

Paldimycin (antibiotic 273a1) and antibiotic 273a2 as well as their individual components, paldimycins A (273a1 alpha) and B (273a1 beta) and antibiotics 273a2 alpha and 273a2 beta were synthesized from paulomycin, paulomycin A and paulomycin B, respectively, by reacting with N-acetyl-L-cysteine. The semisynthetic antibiotics had chromatographic behavior (TLC, HPLC) and physical and chemical properties identical to the properties of the corresponding antibiotics produced by Streptomyces paulus.

Enzymatic phosphorylation of macrolide antibiotics.

Five macrolide antibiotics (erythromycin A, 1; oleandomycin, 3a; tylosin, 4a; spiramycins, 5a; leucomycin A3, 6a) have been phosphorylated enzymatically using cell-free extracts derived from Streptomyces coelicolor UC 5240. The necessary cofactors and the rates of the conversion have been determined.

Isolation, identification and synthesis of a metabolite of tazadolene succinate.

Metabolism of tazadolene (1), a novel non-opioid analgesic with antidepressant properties, affords the 4-hydroxy and 3-methoxy-4-hydroxy derivatives (phenyl ring) of the drug, and N-[2-(phenylmethylene)cyclohexyl]-beta-alanine (4). The isolation, identification and synthesis of the latter metabolite is described.

Desertomycin: purification and physical-chemical properties.

Desertomycin was isolated from Streptomyces macronensis Dietz sp. nov. UC 8271.

The chemistry of the rubradirins. I. The structures of rubransarols A and B.

The antibiotic rubradirin, C48H46N4O20 was cleaved at an ester function by aqueous methylamine into rubransarol A, C23H23NO8, and a methyl amide, C26H28N4O12. Rubradirin B, C40H33N3O15, was similarly cleaved in methanolic ammonia into rubransarol B, C23H23NO8, and the primary amide, C17H13N3O7. The rubransarols are shown to be unique ansamycins which are isomeric at a double bond in the large ring.