| 6988430 |
Accumulation of glyceride-containing precursor of the outer membrane lipoprotein in the cytoplasmic membrane of Escherichia coli treated with globomycin |
None |
J Biol Chem |
Accumulation of glyceride-containing precursor of the outer membrane lipoprotein in the cytoplasmic membrane of Escherichia coli treated with globomycin
Abstract
- The protein accumulated in the cell envelope of Escherichia coli treated with globomycin was identified as the precursor of the outer membrane lipoprotein. The prolipoprotein was almost exclusively localized in the cytoplasmic membrane. The prolipoprotein could be immunoprecipitated with antilipoprotein immunoglobulin and could be chased to the lipoprotein in both in vivo and in vitro. Globomycin inhibited the chase. The prolipoprotein contained glycerol and fatty acid residues, whereas no free sulfhydryl group was detected in it. From these results, it is concluded that the prolipoprotein possesses a glyceride which is covalently bound to the cysteine residue in the peptide as the lipoprotein does and that the removal of signal peptide takes place after the modification. The inhibition of bacterial growth with increasing concentrations of globomycin was accompanied by a gradual increase in the accumulation of the prolipoprotein. Furthermore, growth of the lipoprotein-negative mutant was highly resistant to globomycin. These results strongly indicate that the accumulation of the prolipoprotein in the cytoplasmic membrane causes the death of cells.
|
| 7014556 |
Peptide toxins from Conus geographus venom |
None |
J Biol Chem |
Peptide toxins from Conus geographus venom
Abstract
- Three homologous toxic peptides which cause postsynaptic inhibition at the vertebrate neuromuscular junction have been purified from the venom of the marine snail Conus geographus. Their amino acid sequences are: (formula see text) The biologically active peptides are monomeric, with internal disulfide bonds.
|
| 7055563 |
Action of peptidolipidic antibiotics of the iturin group on erythrocytes. Effect of some lipids on hemolysis |
10.1016/0005-2736(82)90007-4. |
Biochim Biophys Acta |
Action of peptidolipidic antibiotics of the iturin group on erythrocytes. Effect of some lipids on hemolysis
Abstract
- Iturin A, bacillomycin L and bacillomycin L dimethyl ester have a strong lytic activity upon human erythrocytes while iturin C is totally inactive. The hemolytic action of the antibiotics is inhibited by free cholesterol as well as by cholesterol included in mixed liposomes of phosphatidylcholine-cholesterol and to a lesser extent by phosphatidylcholine liposomes. This inhibition is the result of an interaction between the antibiotic and added lipids which diminishes the concentration of free antibiotic available to lyse erythrocytes. The inhibitory effect of liposomes on hemolysis demonstrated the affinity of the antibiotic for artificial membrane, especially those containing cholesterol.
|
| 7058681 |
Activation and clearance of a hormonogen, triglycyl-oxytocin, in the conscious dog |
10.1530/acta.0.0990211. |
Acta Endocrinol (Copenh) |
Activation and clearance of a hormonogen, triglycyl-oxytocin, in the conscious dog
Abstract
- Triglycyl-oxytocin (TGOT) and oxytocin (OT) were administered iv and sc to conscious dogs and the plasma concentrations of these peptides determined simultaneously by RIA and bioassay. Constant iv infusions (1 h) at 23 pmol/kg/min produced plateau levels of 1.1 and 1.6 pmol/ml plasma for OT and TGOT respectively. Whilst the distribution space was similar for each peptide. TGOT persisted longer in the circulation (t1/2, for TGOT 6.6 min; for OT 4.2 min). Bioactive values for OT followed RIA values whether this peptide was given iv or sc. Although very little bioactivity was generated by iv infusions of TGOT, considerable amounts of bioactive OT were found in plasma after injection of TGOT subcutaneously. The hormonogen proved relatively resistant to oxytocinase, an enzyme that destroys OT rapidly. Our results indicate that TGOT is converted to OT in vivo and that its action as a hormonogen is more pronounced after sc than iv administration.
|
| 7060798 |
Effect of arginine vasotocin, oxytocin and their fragments on the corticosterone content in the blood plasma of chickens of different ages |
None |
Fiziol Zh SSSR Im I M Sechenova |
Effect of arginine vasotocin, oxytocin and their fragments on the corticosterone content in the blood plasma of chickens of different ages
Abstract
- Administration of arginin-vasotocin, oxytocin and their fragments had no effect on corticosterone content in the blood plasma of 10-month chickens whereas in 20 and 30-day chickens arginin-vasotocin and its terminal fragment: amid of prolyl-arginil-glycil, considerably increased the corticosterone content. The cyclic fragment of these hormones: tocinic acid, proved ineffective. The adrenocorticotropic effect of arginin-vasotocin obvious in young chickens seems to be due to the terminal part of the molecule.
|
| 7118089 |
The cyclized C-terminal dipeptide of arginine vasopressin: metabolic stability and antagonism of puromycin-induced amnesia |
10.1016/0018-506x(82)90022-8. |
Horm Behav |
The cyclized C-terminal dipeptide of arginine vasopressin: metabolic stability and antagonism of puromycin-induced amnesia
Abstract
|
| 7118384 |
Cyclic peptides. XII. Synthesis of AM-toxin III and its analogs |
None |
Int J Pept Protein Res |
Cyclic peptides. XII. Synthesis of AM-toxin III and its analogs
Abstract
- A cyclic tetradepsipeptide with a sequence corresponding to AM-toxin III (a phytotoxic peptide) was synthesized by a conventional method in order to confirm the proposed structure. This was mediated through a deamination reaction of precursor cyclotetradepsipeptide containing a D-2, 3-diaminopropionic acid residue by the Hofmann degradation method. The synthetic peptide and natural AM-toxin III were identical in regard to t.l.c., crystal form, mass spectrum and biological activity in causing necrosis on apple leaves. Two analogs, l-O-methyl-L-tyrosine-AM-toxin and l-L-tyrosine-AM-toxin showed extremely weak activity; the relationship between the bulkiness of an aromatic side chain at position 1 of AM-toxin III and its biological activity is discussed.
|
| 7118410 |
Coordination chemistry of peptides. Part II. Crystal structure of cyclo-L-methionylglycine and studies of metal complexation |
None |
Int J Pept Protein Res |
Coordination chemistry of peptides. Part II. Crystal structure of cyclo-L-methionylglycine and studies of metal complexation
Abstract
- The structure of the title compound displays a nearly planar diketopiperazine ring. The side chain is folded on the ring, the S atom making a significantly short contact with the methionine carbonyl atom. The crystal packing shows an unusual assembly of alternating layers of peptide and crystallization water molecules. The side chain sulfur atom is found to be the primary site for metal coordination of the ligand, while in some systems there is evidence of additional coordination through deprotonated amide nitrogens.
|
| 7118425 |
Allomalformin |
None |
Int J Pept Protein Res |
Allomalformin
Abstract
- In an attempt to find explanation for the initial erroneous sequence assignment for malformin, a sequence-isomer of the natural product, 3-isoleucine-5-valine malformin or briefly "allomalformin" that on partial acid hydrolysis could have given rise to misleading fragments, was synthesized and compared with both natural and synthetic preparations of malformin. Allomalformin is identical to the parent microbial peptide (malformin A, or briefly malformin) with respect to biological activity and conformation (ORD and CD spectra) and is indistinguishable from it by high pressure liquid chromatography. Yet, the two isomers have slightly different Rf values on thin-layer chromatograms and by this method no allomalformin could be detected in samples of the natural product. On the other hand both high pressure liquid chromatography and thin-layer chromatography demonstrated the presence of the lower homolog, 5-valine malformin, in the samples examined. On partial acid hydrolysis this natural analog should liberate Val-Cys, while Cys-Val forms from malformin itself. Similarly, the corresponding desthio cyclopentapeptides should give rise to Val-Ala and Ala-Val respectively; the former being more resistant to further hydrolysis persists in the partial hydrolysates. The presence of Val-Cys in partial hydrolysates of malformin and of Val-Ala in the partial hydrolysates of desthiomalformin, both originating from the accompanying lower homolog rather than from malformin itself, is likely to have led to the postulation of the erroneous Cys-Val-Cys partial sequence.
|
| 7129757 |
Cyclic peptides. XIV. Syntheses of 4-l-leucine-, 4-D-leucine-, and 3-L-proline, 4-D-leucine-Cyl-2 |
None |
Int J Pept Protein Res |
Cyclic peptides. XIV. Syntheses of 4-l-leucine-, 4-D-leucine-, and 3-L-proline, 4-D-leucine-Cyl-2
Abstract
- Cyl-2 is a phytotoxic cyclic tetrapeptide with the sequence of cyclo(D-Tyr(Me)-L-Ile-L-Pip-Aoe-): Aoe, 2-amino-8-oxo-9,10-epoxydecanoic acid. The configuration of Aoe is unknown. Three analogs, cyclo(-D-Try(Me)-L-Ile-L-Pip-L(and D)-Leu-) (1 and 2) and cyclo(-D-Tyr(Me)-L-Ile-L-Pro-D-Leu-) (3), were synthesized and spectroscopic features of these analogs were compared. 1H-N.m.r. spectra of cyclo(D-Tyr(Me)-L-Ile-L-Pip-L-Leu) (1), cyclo(-D-Tyr(Me)-L-Ile-L-Pro-L-Leu-) (4), and Cyl-2 showed a similar pattern. On the other hand, the spectra of analogs 2 and 3 showed a different pattern, the Ile-Pro bond in 3 being in cis conformation.
|
| 7143358 |
Carbon-7 substituted actinomycin D analogues as improved antitumor agents: synthesis and DNA-binding and biological properties |
10.1021/jm00352a023. |
J Med Chem |
Carbon-7 substituted actinomycin D analogues as improved antitumor agents: synthesis and DNA-binding and biological properties
Abstract
- 7-(2,3-Epoxypropoxy)actinomycin D has been synthesized along with its major companion product, 7-(2,3-dihydroxypropoxy)actinomycin D. They were characterized by UV-visible and CD spectra and by NMR studies. According to UV-visible absorptiometry, circular dichroism, and thermal denaturation studies, they bind to DNA in a manner that is comparable to actinomycin D. The analogues are, like actinomycin D, extremely cytotoxic to human lymphoblastic leukemic cells (CCRF-CEM) in vitro but are significantly less toxic than actinomycin D to normal CDF1 mice is vivo. Unlike actinomycin, these analogues are metabolized in rats, and the metabolites are excreted in rat urine at a rapid rate. Compared to actinomycin D, the antitumor activity of the 7-(2,3-epoxypropoxy)actinomycin analogue against P-388 leukemia in mice is decidedly superior, and the therapeutic index is improved several fold.
|
| 7151959 |
Reversible depression of spontaneous brain electrical activity induced by actinomycin D and 7-aminoactinomycin D in rats |
10.1007/BF01955760. |
Experientia |
Reversible depression of spontaneous brain electrical activity induced by actinomycin D and 7-aminoactinomycin D in rats
Abstract
- Various types of actinomycin (C,D,S2, I and V) and 7-amino-analogue of actinomycin D were injected into the right lateral ventricle of the brain through a chronically implanted cannula. In rats but not in mice actinomycin D, actinomycin S2 and 7-aminoactinomycin D caused depression of EEG, while cardiac and respiratory activity were maintained. This effect of the EEG was reversible and a normal EEG pattern reappeared at least 3 h after administration.
|
| 7155141 |
Physico-chemical properties of the complexes of bacitracin with DNA and its effect on the process of transcription in vitro |
None |
Mol Biol (Mosk) |
Physico-chemical properties of the complexes of bacitracin with DNA and its effect on the process of transcription in vitro
Abstract
- The aim of the present paper was to study the action of one of the peptide antibiotics, bacitracin, as the regulator of gene activity at the transcription level. Therefore the commercial bacitracin has been fractionated into two main parts by paper chromotography. These two fractions have been identified as bacitracin A (biologically active) and bacitracin F (biologically inactive). The binding of both fractions to DNA has been studied. It has been shown that bacitracin A stabilizes DNA to a lesser degree than bacitracin F does. DNA-bacitracin complexes are formed in the major groove of the DNA helix by hydrogen bonds. The analysis of the the obtained experimental data allows us to suppose that bacitracin binding to DNA has a very specific character and that this antibiotic may act as the regulator of gene activity.
|
| 7168869 |
Studies on analgesic oligopeptides. II. Structure-activity relationship among thirty analogs of a cyclic dipeptide, cyclo(-Tyr-Arg-) |
10.1248/cpb.30.4435. |
Chem Pharm Bull (Tokyo) |
Studies on analgesic oligopeptides. II. Structure-activity relationship among thirty analogs of a cyclic dipeptide, cyclo(-Tyr-Arg-)
Abstract
|
| 7174204 |
Unusual intramolecular hydrogen bonding in cycloamanide A, cyclic (LPro-LVal-LPhe-LPhe-LAla-Gly). A crystal structure analysis |
10.1111/j.1399-3011.1982.tb03061.x. |
Int J Pept Protein Res |
Unusual intramolecular hydrogen bonding in cycloamanide A, cyclic (LPro-LVal-LPhe-LPhe-LAla-Gly). A crystal structure analysis
Abstract
- The naturally occurring cyclic hexapeptide, cycloamanide A, has only one intramolecular hydrogen bond. It is a 4 leads to 1 type that encompasses the L Phe-L Ala sequence in which the experimentally determined phi, psi values are +54 degrees, -118 degrees and -88 degrees, -4 degrees, respectively. Even though the chirality is L, L, the phi, psi values are characteristic for a D, L beta-bend, Type II'. The conformation of the molecule was established by a crystal structure determination using X-ray diffraction analysis. Cycloamanide A (C33H42N6O6 . 4H2O) crystallizes in space group P2(1)2(1)2(1) with cell parameters a = 13.307(2) A, b = 24.820(4)A and c = 11.231(1)A."
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