9. Structure - Juvenile Activity Relationships in simple Peptides

1971 ◽  
Vol 26 (7) ◽  
pp. 719-722 ◽  
Author(s):  
Karel Poduška ◽  
František Šorm ◽  
Karel Sláma
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Juvenile Hormone ◽  
Specific Activity ◽  
Hormonal Activity ◽  
Aminobenzoic Acid ◽  
The Family ◽  
Juvenile Hormone Analogues ◽  
Acid Ethylester

Systematic alterations of the central amino acid in the peptidic juvenile hormone analogues consisting of three parts connected by amidic bonds tert.-butyloxycarbonyl group - amino acid - p-aminobenzoic acid ethylester) have revealed that the hormonal activity is dependent on the L-configuration of the central amino acids. The compounds exhibit specific activity on insects of the family Pyrrhocoridae, being inactive on several other insects tested.

scholarly journals Site-directed mutagenesis at aspartate and glutamate residues of xylanase from Bacillus pumilus

1992 ◽  
Vol 288 (1) ◽  
pp. 117-121 ◽  
Author(s):  
E P Ko ◽  
H Akatsuka ◽  
H Moriyama ◽  
A Shinmyo ◽  
Y Hata ◽  
...  
Keyword(s):  
Amino Acids ◽  
Reaction Mechanism ◽  
Amino Acid ◽  
Bacillus Pumilus ◽  
Specific Activity ◽  
Sequence Similarity ◽  
Site Directed Mutagenesis ◽  
Dimensional Structure ◽  
Amino Acid Sequence Similarity ◽  
Directed Mutagenesis

To elucidate the reaction mechanism of xylanase, the identification of amino acids essential for its catalysis is of importance. Studies have indicated the possibility that the reaction mechanism of xylanase is similar to that of hen's egg lysozyme, which involves acidic amino acid residues. On the basis of this assumption, together with the three-dimensional structure of Bacillus pumilus xylanase and its amino acid sequence similarity to other xylanases of different origins, three acidic amino acids, namely Asp-21, Glu-93 and Glu-182, were selected for site-directed mutagenesis. The Asp residue was altered to either Ser or Glu, and the Glu residues to Ser or Asp. The purified mutant xylanases D21E, D21S, E93D, E93S, E182D and E182S showed single protein bands of about 26 kDa on SDS/PAGE. C.d. spectra of these mutant enzymes show no effect on the secondary structure of xylanase, except that of D21E, which shows a little variation. Furthermore, mutations of Glu-93 and Glu-182 resulted in a drastic decrease in the specific activity of xylanase as compared with mutation of Asp-21. On the basis of these results we propose that Glu-93 and Glu-182 are the best candidates for the essential catalytic residues of xylanase.

Amino Acid Metabolism in Plants. III. Purification and Some Properties of a Multispecific Aminotransferase Isolated from Bushbean Seedlings (Phaseolus vulgaris L.)

1972 ◽  
Vol 50 (7) ◽  
pp. 813-829 ◽  
Author(s):  
J. C. Forest ◽  
F. Wightman
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Aspartic Acid ◽  
Aspartate Aminotransferase ◽  
Soluble Protein ◽  
Specific Activity ◽  
Aromatic Amino Acids ◽  
Total Activity ◽  
Aminotransferase Activity ◽  
Aromatic Aminotransferase

The development of aromatic aminotransferase activity was examined in cotyledons, roots, and shoots of bushbean seedlings growing under light or dark conditions for the first 2 weeks after germination. All three aromatic amino acid – α-ketoglutarate aminotransferase activities were found to have similar patterns of development in comparable organs grown under the two environmental conditions, and the changes in levels of activity appeared unrelated to variations in the endogenous amounts of free aromatic amino acids in the organs of these seedlings. The highest total activity for all three transamination reactions was found in the shoots of light-grown seedlings after 14 days, whereas the aminotransferases showing highest specific activity were found in roots of both kinds of seedlings after 8 days of growth. The intracellular distribution of the three aromatic aminotransferase activities and of aspartate aminotransferase activity was investigated by differential centrifugation of root homogenates. Only a total of 10% of these two activities was found in the two particulate fractions; the soluble protein in the final supernatant fraction accounted for almost 90% of the total aromatic and aspartate aminotransferase activities.The aromatic aminotransferase in the soluble protein fraction from seedling roots was purified about 600-fold by pH precipitation, ammonium sulfate fractionation, and Sephadex chromatography, and the recovery obtained was 30–35% based on total activity. It was observed that the specific activity for aspartate–α-ketoglutarate aminotransferase increased proportionally to the increase in aromatic aminotransferase activities during the different steps of purification. Gel electrophoresis of the purified fraction revealed only one protein band which corresponded to the product-specific stained band for the three aromatic aminotransferase activities assayed on other gels. The molecular weight of the purified aminotransferase was found to be about 128 000 daltons and its Stokes radius was calculated to be 43 ± 3 Å. The pH optima for the three aromatic aminotransferase activities and for aspartate aminotransferase activity were all found to be 8.5. The purified enzyme showed no specific requirement for pyridoxal phosphate and an examination of its amino acid substrate specificity revealed that it was able to catalyze transamination of L-aspartic acid, L-phenylalanine, L-tyrosine, and L-tryptophan when α-ketoglutarate was provided as amino group acceptor. The enzyme was also found to catalyze transamination of L-glutamic acid when oxaloacetate was used as amino group acceptor, but neither pyruvate nor glyoxylate were utilized as amino acceptors for transamination of any of the amino acids examined. The enzyme was found to catalyze transamination of aspartic acid with much greater velocity than its rate of reaction with any of the three aromatic amino acids, and the inclusion of aspartic acid in a reaction medium at equimolar concentration with any one of the three aromatic amino acids resulted in strong inhibition of the aromatic aminotransferase activity of the enzyme. All the evidence indicates that the soluble protein fraction purified from bushbean roots contained only one aminotransferase which was able to catalyze the transamination of five L-amino acids. The demonstration of the substrate multispeciftcity of this pure enzyme represents the first evidence for a multispecific aminotransferase in plants.

scholarly journals A Mating-Induced Protein of Phytophthora infestans Is a Member of a Family of Elicitors with Divergent Structures and Stage-Specific Patterns of Expression

2003 ◽  
Vol 16 (10) ◽  
pp. 926-935 ◽  
Author(s):  
Anna-Liisa Fabritius ◽  
Howard S. Judelson
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Gene Family ◽  
Phytophthora Infestans ◽  
Amino Acid Identity ◽  
Acid Identity ◽  
Terminal Domain ◽  
Defense Reactions ◽  
The Family ◽  
Microbe Interactions

Five members of an elicitor-like gene family from Phytophthora infestans were examined. The family was identified through the analysis of M81, a mating-induced gene. The predicted M81 product resembled a 42-kDa P. sojae glycoprotein known to elicit defense reactions in plants, including a host of P. infestans, potato. M81 was the most structurally and functionally divergent of the P. infestans genes compared with the P. sojae sequence. M81 lacked elicitor activity, had the lowest protein identity (47%), displayed mating-specific transcription, and had a novel C-terminal domain. The latter contained a 30-residue proline- and threonine-rich motif, which, remarkably, was tandemly repeated 24 to 36 times in different alleles. M81C, M81D, and M81E better resembled the P. sojae protein based on amino acid identity (63 to 75%) and conserved elicitor activity. M81C and M81D mRNA accumulated only during zoosporogenesis, while M81E expression was restricted to hyphae. M81B, an apparent pseudogene, was physically linked to M81. The protein products of each gene were predicted to be extracellular transglutaminases ranging in size from 436 to 1,607 amino acids. Genes with an elicitor, proline- and threonine-rich repeat, and both elicitor and repeat domains were widely distributed throughout Phytophthora infestans. These findings help explain the natural functions of elicitors in pathogen biology and plant-microbe interactions.

scholarly journals Fate of dietary sucrose and neosynthesis of amino acids in the pea aphid, acyrthosiphon pisum, reared on different diets

1999 ◽  
Vol 202 (19) ◽  
pp. 2639-2652 ◽  
Author(s):  
G. Febvay ◽  
Y. Rahbe ◽  
M. Rynkiewicz ◽  
J. Guillaud ◽  
G. Bonnot
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Amino Acid Composition ◽  
Acid Composition ◽  
Acyrthosiphon Pisum ◽  
Specific Activity ◽  
Essential Amino Acids ◽  
Pea Aphid ◽  
Natural Food ◽  
Pea Aphids

The fate of sucrose, the major nutrient of an aphid's natural food, was explored by radiolabeling in the pea aphid Acyrthosiphon pisum. To investigate the influence of nitrogen quality of food on amino acid neosynthesis, pea aphids were reared on two artificial diets differing in their amino acid composition. The first (diet A) had an equilibrated amino acid balance, similar to that derived from analysis of aphid carcass, and the other (diet B) had an unbalanced amino acid composition similar to that of legume phloem sap. Aphids grown on either diet expired the same quantity of sucrose carbon as CO(2), amounting to 25–30 % of the ingested sucrose catabolized in oxidation pathways. On diet A, the aphids excreted through honeydew about twice as much sucrose carbon as on diet B (amounting to 12.6 % of the ingested sucrose for diet A and 8.4 % for diet B), while amounts of sucrose carbons incorporated into exuviae were almost identical (1.9 % of the ingested sucrose on diet A and 2.7 % on diet B). There was also no difference in the amounts of sucrose carbon incorporated into the aphid tissues, which represented close to 50 % of the ingested sucrose. Sucrose carbons in the aphid tissues were mainly incorporated into lipids and the quantities involved were the same in aphids reared on either diet. On diet B, we observed neosynthesis of all protein amino acids from sucrose carbons and, for the first time in an aphid, we directly demonstrated the synthesis of the essential amino acids leucine, valine and phenylalanine. Amino acid neosynthesis from sucrose was significantly higher on diet B (11.5 % of ingested sucrose carbons) than on diet A (5.4 %). On diet A, neosynthesis of most of the amino acids was significantly diminished, and synthesis of two of them (histidine and arginine) was completely suppressed. The origin of amino acids egested through honeydew was determined from the specific activity of the free amino acid pool in the aphid. Aphids are able to adjust to variation in dietary amino acids by independent egestion of each amino acid. While more than 80 % of excreted nitrogen was from food amino acids, different amino acids were excreted in honeydew of aphids reared on the two diets. The conversion yields of dietary sucrose into aphid amino acids determined in this study were combined with those obtained previously by studying the fate of amino acids in pea aphids reared on diet A. The origin of all the amino acid carbons in aphid tissues was thus computed, and the metabolic abilities of aphid are discussed from an adaptive point of view, with respect to their symbiotic status.

Incorporation of carbon atoms from glucose into free amino acids in brain under normal and altered conditions

1970 ◽  
Vol 48 (3) ◽  
pp. 228-235 ◽  
Author(s):  
Y. Yoshino ◽  
K. A. C. Elliott
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Aspartic Acid ◽  
Free Amino Acids ◽  
Free Amino ◽  
Acid Level ◽  
Specific Activity ◽  
Specific Radioactivity ◽  
Aminobutyric Acid ◽  
Aminooxyacetic Acid

The time course of entry of radioactive carbon from intravenously administered [U-14C]-glucose into free amino acids in the brains of rats has been studied using an automatic amino acid analyzer coupled through a flow cell with a scintillation counter. Radioactivity appeared rapidly in alanine, aspartic acid, glutamic acid, glutamine, and γ-aminobutyric acid as previously shown, and in an unknown ninhydrin-positive substance present in very small amount. Urea, serine, and glycine became slightly radioactive. Four hours after giving the radioactive glucose, the specific activity in all soluble substances was low. In pentobarbital anesthesia, specific radioactivity was increased in alanine and decreased in γ-aminobutyric acid, aspartic and glutamic acids, and glutamine. A high proportion of radioactivity remained in glucose. Under hypoxia, alanine increased in amount but decreased in specific activity, and the specific activities of the other strongly labelled amino acids decreased. The proportion of the total radioactivity found in glucose and lactate increased. During picrotoxin and pentylenetetrazol convulsions, changes occurred which were similar to those under hypoxia. After aminooxyacetic acid administration, the well-known great increase in γ-aminobutyric acid level was found to be accompanied by a decrease in glutamate and also in aspartic acid and alanine, indicating inhibition of the three transaminases concerned. The previously observed brief rapid postmortem increase in the amount of γ-aminobutyric acid was confirmed; alanine also increased briefly but no other amino acid did so. The increased γ-aminobutyric acid had the same specific radioactivity as the original but the extra alanine was less radioactive than the original. When the γ-aminobutyric acid level had been increased by administration of aminooxyacetic acid, the rapid postmortem increase did not occur.

scholarly journals Auto-Inhibition and Partner Proteins, Core-Binding Factor β (CBFβ) and Ets-1, Modulate DNA Binding by CBFα2 (AML1)

2000 ◽  
Vol 20 (1) ◽  
pp. 91-103 ◽  
Author(s):  
Ting-Lei Gu ◽  
Tamara L. Goetz ◽  
Barbara J. Graves ◽  
Nancy A. Speck
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Dna Binding ◽  
Bone Development ◽  
Intramolecular Interactions ◽  
Runt Domain ◽  
Core Binding Factor ◽  
Binding Factor ◽  
The Family ◽  
Partner Proteins

ABSTRACT Core-binding factor α2 (CBFα2; otherwise known as AML1 or PEBP2αB) is a DNA-binding subunit in the family of core-binding factors (CBFs), heterodimeric transcription factors that play pivotal roles in multiple developmental processes in mammals, including hematopoiesis and bone development. The Runt domain in CBFα2 (amino acids 51 to 178) mediates DNA binding and heterodimerization with the non-DNA-binding CBFβ subunit. Both the CBFβ subunit and the DNA-binding protein Ets-1 stimulate DNA binding by the CBFα2 protein. Here we quantify and compare the extent of cooperativity between CBFα2, CBFβ, and Ets-1. We also identify auto-inhibitory sequences within CBFα2 and sequences that modulate its interactions with CBFβ and Ets-1. We show that sequences in the CBFα2 Runt domain and sequences C terminal to amino acid 214 inhibit DNA binding. Sequences C terminal to amino acid 214 also inhibit heterodimerization with the non-DNA-binding CBFβ subunit, particularly heterodimerization off DNA. CBFβ rescinds the intramolecular inhibition of CBFα2, stimulating DNA binding approximately 40-fold. In comparison, Ets-1 stimulates CBFα2 DNA binding 7- to 10-fold. Although the Runt domain alone is sufficient for heterodimerization with CBFβ, sequences N terminal to amino acid 41 and between amino acids 190 and 214 are required for cooperative DNA binding with Ets-1. Cooperative DNA binding with Ets-1 is less pronounced with the CBFα2-CBFβ heterodimer than with CBFα2 alone. These analyses demonstrate that CBFα2 is subject to both negative regulation by intramolecular interactions, and positive regulation by two alternative partnerships.

scholarly journals DNA sequence homology between the terminal inverted repeats of Shope fibroma virus and an endogenous cellular plasmid species

1986 ◽  
Vol 6 (1) ◽  
pp. 265-276
Author(s):  
C Upton ◽  
G McFadden
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Sequence Homology ◽  
Inverted Repeat ◽  
Specific Activity ◽  
High Specific Activity ◽  
Cesium Chloride ◽  
Open Reading Frame ◽  
Terminal Inverted Repeat ◽  
Reading Frame

DNA hybridization experiments indicate that the genome of a tumorigenic poxvirus. Shope fibroma virus (SFV), possesses sequence homology with DNA isolated from uninfected rabbit cells. Southern blotting experiments, either with high-complexity rabbit DNA as probe and SFV restriction fragments as targets or with high-specific activity, 32P-labeled, cloned SFV sequences as probes and rabbit DNA as target, indicate that the homologous sequences map at two locations within the viral genome, one in each copy of the terminal inverted repeat sequences. Unexpectedly, Southern blots revealed that the homologous host sequences reside in a rabbit extrachromosomal DNA element. This autonomous low-molecular-weight DNA species could be specifically amplified by cycloheximide treatment and was shown by isopycnic centrifugation in cesium chloride-ethidium bromide to consist predominantly of covalently closed circular DNA molecules. DNA sequencing of pSIC-9, a cloned 1.9-kilobase fragment of the rabbit plasmid species, indicated extensive homology at the nucleotide level over a 1.5-kilobase stretch of the viral terminal inverted repeat. Analysis of open reading frames in both the plasmid and SFV DNA revealed that (i) the N-terminal 157-amino acid sequence of a potential 514-amino acid SFV polypeptide is identical to the N-terminal 157 amino acids of one pSIC-9 open reading frame, and (ii) a second long pSIC-9 open reading frame of 361 amino acids, although significantly diverged from the comparable nucleotide sequence in the virus, possessed considerable homology to a family of cellular protease inhibitors, including alpha 1-antichymotrypsin, alpha 1-antitrypsin, and antithrombin III. The potential role of such cellular plasmid-like DNA species as a mediator in the exchange of genetic information between the host cell and a cytoplasmically replicating poxvirus is discussed.

scholarly journals Identification of Bacillus thuringiensisDelta-Endotoxin Cry1C Domain III Amino Acid Residues Involved in Insect Specificity

1999 ◽  
Vol 65 (10) ◽  
pp. 4369-4374 ◽  
Author(s):  
Ruud A. de Maagd ◽  
Petra Bakker ◽  
Nikola Staykov ◽  
Stefan Dukiandjiev ◽  
Willem Stiekema ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Spodoptera Exigua ◽  
Specific Activity ◽  
Beet Armyworm ◽  
Amino Acid Residues ◽  
Optimal Activity ◽  
Amino Acid Insertion ◽  
Negative Effect ◽  
Domain Iii

ABSTRACT Cry1C domain III amino acid residues involved in specificity for beet armyworm (Spodoptera exigua) were identified. For this purpose, intradomain III hybrids between Cry1E (nontoxic) and Cry1E-Cry1C hybrid G27 (toxic) were made. Crossover points of these hybrids defined six sequence blocks containing between 1 and 19 of the amino acid differences between Cry1E and G27. Blocks B, C, D, and E of G27 were shown to be required for optimal activity against S. exigua. Block E was also required for optimal activity against the tobacco hornworm (Manduca sexta), whereas block D had a negative effect on toxicity for this insect. The mutagenesis of individual amino acids in block B identified Trp-476 as the only amino acid in this block essential, although not sufficient by itself, for full S. exigua activity. In block D, we identified a seven-amino-acid insertion in G27 that was not in Cry1E. The deletion of either one of two groups of four consecutive amino acids in this insertion completely abolished activity against S. exiguabut resulted in higher activity against M. sexta. Alanine substitutions of the first group had little effect on toxicity, whereas alanine substitutions of the second group had the same effect as its deletion. These results identify groups of amino acids as well as some individual residues in Cry1C domain III, which are strongly involved inS. exigua-specific activity as well as sometimes involved in M. sexta-specific activity.

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