scholarly journals Acetamido Sugar Biosynthesis in the Euryarchaea

2008 ◽  
Vol 190 (8) ◽  
pp. 2987-2996 ◽  
Author(s):  
Seema C. Namboori ◽  
David E. Graham
Keyword(s):  
Biosynthetic Pathway ◽  
Comparative Sequence Analysis ◽  
Core Oligosaccharide ◽  
Methanococcus Maripaludis ◽  
The Core ◽  
Capsule Production ◽  
Lipopolysaccharide Biosynthesis ◽  
Genes Encoding ◽  
Large Families ◽  
Coenzyme B

ABSTRACT Archaea and eukaryotes share a dolichol phosphate-dependent system for protein N-glycosylation. In both domains, the acetamido sugar N-acetylglucosamine (GlcNAc) forms part of the core oligosaccharide. However, the archaeal Methanococcales produce GlcNAc using the bacterial biosynthetic pathway. Key enzymes in this pathway belong to large families of proteins with diverse functions; therefore, the archaeal enzymes could not be identified solely using comparative sequence analysis. Genes encoding acetamido sugar-biosynthetic proteins were identified in Methanococcus maripaludis using phylogenetic and gene cluster analyses. Proteins expressed in Escherichia coli were purified and assayed for the predicted activities. The MMP1680 protein encodes a universally conserved glucosamine-6-phosphate synthase. The MMP1077 phosphomutase converted α-d-glucosamine-6-phosphate to α-d-glucosamine-1-phosphate, although this protein is more closely related to archaeal pentose and glucose phosphomutases than to bacterial glucosamine phosphomutases. The thermostable MJ1101 protein catalyzed both the acetylation of glucosamine-1-phosphate and the uridylyltransferase reaction with UTP to produce UDP-GlcNAc. The MMP0705 protein catalyzed the C-2 epimerization of UDP-GlcNAc, and the MMP0706 protein used NAD+ to oxidize UDP-N-acetylmannosamine, forming UDP-N-acetylmannosaminuronate (ManNAcA). These two proteins are similar to enzymes used for proteobacterial lipopolysaccharide biosynthesis and gram-positive bacterial capsule production, suggesting a common evolutionary origin and a widespread distribution of ManNAcA. UDP-GlcNAc and UDP-ManNAcA biosynthesis evolved early in the euryarchaeal lineage, because most of their genomes contain orthologs of the five genes characterized here. These UDP-acetamido sugars are predicted to be precursors for flagellin and S-layer protein modifications and for the biosynthesis of methanogenic coenzyme B.

scholarly journals Identification of the Linkage between A-Polysaccharide and the Core in the A-Lipopolysaccharide of Porphyromonas gingivalis W50

2015 ◽  
Vol 197 (10) ◽  
pp. 1735-1746 ◽  
Author(s):  
Nikolay Paramonov ◽  
Joseph Aduse-Opoku ◽  
Ahmed Hashim ◽  
Minnie Rangarajan ◽  
Michael A. Curtis
Keyword(s):  
Porphyromonas Gingivalis ◽  
Biosynthetic Pathway ◽  
Attachment Site ◽  
Outer Core ◽  
Etiologic Agent ◽  
Core Oligosaccharide ◽  
Content Type ◽  
The Core ◽  
O Antigen ◽  
Mutant Strains

ABSTRACTPorphyromonas gingivalissynthesizes two lipopolysaccharides (LPSs), O-LPS and A-LPS. The structure of the core oligosaccharide (OS) of O-LPS and the attachment site of the O-polysaccharide (O-PS) repeating unit [→3)-α-d-Galp-(1→6)-α-d-Glcp-(1→4)-α-l-Rhap-(1→3)-β-d-GalNAcp-(1→] to the core have been elucidated using the ΔPG1051 (WaaL, O-antigen ligase) and ΔPG1142 (Wzy, O-antigen polymerase) mutant strains, respectively. The core OS occurs as an “uncapped” glycoform devoid of O-PS and a “capped” glycoform that contains the attachment site of O-PS via β-d-GalNAc at position O-3 of the terminal α-(1→3)-linked mannose (Man) residue. In this study, the attachment site of A-PS to the core OS was determined based on structural analysis of SR-type LPS (O-LPS and A-LPS) isolated from aP. gingivalisΔPG1142 mutant strain by extraction with aqueous hot phenol to minimize the destruction of A-LPS. Application of one- and two-dimensional nuclear magnetic resonance (NMR) spectroscopy in combination with methylation analysis showed that the A-PS repeating unit is linked to a nonterminal α-(1→3)-linked Man of the “capped core” glycoform of outer core OS at position O-4 via a →6)-[α-d-Man-α-(1→2)-α-d-Man-1-phosphate→2]-α-d-Man-(1→ motif. In order to verify that O-PS and A-PS are attached to almost identical core glycoforms, we identified a putative α-mannosyltransferase (PG0129) inP. gingivalisW50 that may be involved in the formation of core OS. Inactivation of PG0129 led to the synthesis of deep-R-type LPS with a truncated core that lacks α-(1→3)-linked mannoses and is devoid of either O-PS or A-PS. This indicated that PG0129 is an α-1,3-mannosyltransferase required for synthesis of the outer core regions of both O-LPS and A-LPS inP. gingivalis.IMPORTANCEPorphyromonas gingivalis, a Gram-negative anaerobe, is considered to be an important etiologic agent in periodontal disease, and among the virulence factors produced by the organism are two lipopolysaccharides (LPSs), O-LPS and A-LPS. The structures of the O-PS and A-PS repeating units, the core oligosaccharide (OS), and the linkage of the O-PS repeating unit to the core OS in O-LPS have been elucidated by our group. It is important to establish whether the attachment site of the A-PS repeating unit to the core OS in A-LPS is similar to or differs from that of the O-PS repeating unit in O-LPS. As part of understanding the biosynthetic pathway of the two LPSs inP. gingivalis, PG0129 was identified as an α-mannosyltransferase that is involved in the synthesis of the outer core regions of both O-LPS and A-LPS.

scholarly journals Identification and Characterization of the Genes Encoding the Core Histones and Histone Variants of Neurospora crassa

Genetics ◽  
2002 ◽  
Vol 160 (3) ◽  
pp. 961-973 ◽  
Author(s):  
Shan M Hays ◽  
Johanna Swanson ◽  
Eric U Selker
Keyword(s):  
Neurospora Crassa ◽  
Histone Variants ◽  
Null Alleles ◽  
Histone Genes ◽  
Histone H4 ◽  
Coding Regions ◽  
The Core ◽  
Genomic Arrangement ◽  
Genes Encoding ◽  
Core Histones

Abstract We have identified and characterized the complete complement of genes encoding the core histones of Neurospora crassa. In addition to the previously identified pair of genes that encode histones H3 and H4 (hH3 and hH4-1), we identified a second histone H4 gene (hH4-2), a divergently transcribed pair of genes that encode H2A and H2B (hH2A and hH2B), a homolog of the F/Z family of H2A variants (hH2Az), a homolog of the H3 variant CSE4 from Saccharomyces cerevisiae (hH3v), and a highly diverged H4 variant (hH4v) not described in other species. The hH4-1 and hH4-2 genes, which are 96% identical in their coding regions and encode identical proteins, were inactivated independently. Strains with inactivating mutations in either gene were phenotypically wild type, in terms of growth rates and fertility, but the double mutants were inviable. As expected, we were unable to isolate null alleles of hH2A, hH2B, or hH3. The genomic arrangement of the histone and histone variant genes was determined. hH2Az and the hH3-hH4-1 gene pair are on LG IIR, with hH2Az centromere-proximal to hH3-hH4-1 and hH3 centromere-proximal to hH4-1. hH3v and hH4-2 are on LG IIIR with hH3v centromere-proximal to hH4-2. hH4v is on LG IVR and the hH2A-hH2B pair is located immediately right of the LG VII centromere, with hH2A centromere-proximal to hH2B. Except for the centromere-distal gene in the pairs, all of the histone genes are transcribed toward the centromere. Phylogenetic analysis of the N. crassa histone genes places them in the Euascomycota lineage. In contrast to the general case in eukaryotes, histone genes in euascomycetes are few in number and contain introns. This may be a reflection of the evolution of the RIP (repeat-induced point mutation) and MIP (methylation induced premeiotically) processes that detect sizable duplications and silence associated genes.

scholarly journals The Activity of Lipid A and Core Components of Bacterial Lipopolysaccharides in the Prevention of the Hypersensitive Response in Pepper

1997 ◽  
Vol 10 (7) ◽  
pp. 926-928 ◽  
Author(s):  
Mari-Anne Newman ◽  
Michael J. Daniels ◽  
J. Maxwell Dow
Keyword(s):  
Hypersensitive Response ◽  
Xanthomonas Campestris ◽  
Lipid A ◽  
Enteric Bacteria ◽  
Core Oligosaccharide ◽  
The Core ◽  
Minimal Structure ◽  
Core Components ◽  
Pre Treatment ◽  
Bacterial Lipopolysaccharides

Pre-treatment of leaves of pepper (Capsicum annuum) with lipopolysaccharide (LPS) preparations from enteric bacteria and Xanthomonas campestris could prevent the hypersensitive response caused by an avirulent X. campestris strain. By use of a range of deep-rough mutants, the minimal structure in Salmonella LPS responsible for the elicitation of this effect was determined to be lipid A attached to a disaccharide of 2-keto-3-deoxyoctulosonate; lipid A alone and the free core oligosaccharide from a Salmonella Ra mutant were not effective. For Xanthomonas, the core oligosaccharide alone had activity although lipid A was not effective. The results suggest that pepper cells can recognize different structures within bacterial LPS to trigger alterations in plant response to avirulent pathogens.

scholarly journals Structure of the core oligosaccharide of a rough-type lipopolysaccharide of Pseudomonas syringae pv. phaseolicola

2004 ◽  
Vol 271 (23-24) ◽  
pp. 4968-4977 ◽  
Author(s):  
Evelina L. Zdorovenko ◽  
Evgeny Vinogradov ◽  
Galina M. Zdorovenko ◽  
Buko Lindner ◽  
Olga V. Bystrova ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
Core Oligosaccharide ◽  
The Core

scholarly journals Pathways and Inborn Errors of Bile Acid Synthesis

Acta Medica ◽  
2019 ◽  
Vol 50 (4) ◽  
pp. 48-56
Author(s):  
Ufuk Bozkurt Obuz ◽  
Incilay Lay
Keyword(s):  
Bile Acid ◽  
Early Diagnosis ◽  
Bile Acids ◽  
Biosynthetic Pathway ◽  
Acid Synthesis ◽  
Bile Acid Synthesis ◽  
Clinical Findings ◽  
Inborn Errors ◽  
Genes Encoding ◽  
Intracellular Compartments

Bile acids are synthesized from cholesterol through 17 different enzymes located in different intracellular compartments of hepatocytes. Defects have been identified in the genes encoding the enzymes involved in the bile acid synthesis pathways and nine different diseases have been identified so far. In this review, four different biosynthetic pathway of bile acids together with disorders of bile acid synthesis is described. In inborn errors of bile acid synthesis clinical findings can range from liver failure to cirrhosis in infancy or progressive neuropathy in adolescence / adulthood. Laboratory analysis of urine profiling of bile acids is important in early diagnosis and early treatment.

scholarly journals Genomic comparison of archaeal conjugative plasmids fromSulfolobus

Archaea ◽  
2004 ◽  
Vol 1 (4) ◽  
pp. 231-239 ◽  
Author(s):  
Bo Greve ◽  
Susanne Jensen ◽  
Kim Brügger ◽  
Wolfram Zillig ◽  
Roger A. Garrett
Keyword(s):  
Sequence Similarity ◽  
Comparative Sequence Analysis ◽  
Genomic Comparison ◽  
Variable Regions ◽  
Integrase Gene ◽  
Significant Sequence Similarity ◽  
Genes Encoding ◽  
Putative Origin ◽  
Main Components ◽  
Intercellular Exchange

All of the known self-transmissable plasmids of the Archaea have been found in the genusSulfolobus. To gain more insight into archaeal conjugative processes, four newly isolated self-transmissable plasmids, pKEF9, pHVE14, pARN3 and pARN4, were sequenced and subjected to a comparative sequence analysis with two earlier sequenced plasmids, pNOB8 and pING1. The analyses revealed three conserved and functionally distinct sections in the genomes. Section A is considered to encode the main components of the conjugative apparatus, where two genes show low but significant sequence similarity to sections of genes encoding bacterial conjugative proteins. A putative origin of replication is located in section B, which is highly conserved in sequence and contains several perfect and imperfect direct and inverted repeats. Further downstream, in section C, an operon encoding six to nine smaller proteins is implicated in the initiation and regulation of replication. Each plasmid carries an integrase gene of the type that does not partition on integration, and there is strong evidence for their integration into host chromosomes, where they may facilitate intercellular exchange of chromosomal genes. Two plasmids contain hexameric short regularly spaced repeats (SRSR), which have been implicated in plasmid maintenance, and each plasmid carries multiple recombination motifs, concentrated in the variable regions, which likely provide sites for genomic rearrangements.

scholarly journals GuUGT, a glycosyltransferase from Glycyrrhiza uralensis , exhibits glycyrrhetinic acid 3- and 30-O-glycosylation

2019 ◽  
Vol 6 (10) ◽  
pp. 191121 ◽  
Author(s):  
Ying Huang ◽  
Da Li ◽  
Jinhe Wang ◽  
Yi Cai ◽  
Zhubo Dai ◽  
...  
Keyword(s):  
Biosynthetic Pathway ◽  
Glycyrrhetinic Acid ◽  
Glycyrrhiza Uralensis ◽  
Transcriptome Data ◽  
Bioactive Components ◽  
Triterpenoid Saponins ◽  
Genes Encoding ◽  
Engineered Yeast ◽  
Biochemical Analyses

Glycyrrhiza uralensis is a well-known herbal medicine that contains triterpenoid saponins as the predominant bioactive components, and these compounds include glycyrrhetinic acid (GA)-glycoside derivatives. Although two genes encoding UDP-glycosyltransferases (UGTs) that glycosylate these derivates have been functionally characterized in G. uralensis , the mechanisms of glycosylation by other UGTs remain unknown. Based on the available transcriptome data, we isolated a UGT with expression in the roots of G. uralensis . This UGT gene possibly encodes a glucosyltransferase that glycosylates GA derivatives at the 3-OH site. Biochemical analyses revealed that the recombinant UGT enzyme could transfer a glucosyl moiety to the free 3-OH or 30-COOH groups of GA. Furthermore, engineered yeast harbouring genes involved in the biosynthetic pathway for GA-glycoside derivates produced GA-3- O -β-D-glucoside, implying that the enzyme has GA 3-O-glucosyltransferase activity in vivo . Our results could provide a frame for understand the function of the UGT gene family, and also is important for further studies of triterpenoids biosynthesis in G. uralensis .

scholarly journals Crosstalk among Indoleamines, Neuropeptides and JH/20E in Regulation of Reproduction in the American Cockroach, Periplaneta americana

Insects ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 155 ◽  
Author(s):  
A. S. M. Kamruzzaman ◽  
Azam Mikani ◽  
Amr A. Mohamed ◽  
Azza M. Elgendy ◽  
Makio Takeda
Keyword(s):  
Oocyte Maturation ◽  
Biosynthetic Pathway ◽  
Periplaneta Americana ◽  
American Cockroach ◽  
Second Step ◽  
Double Stranded Rna ◽  
Vitellogenin Receptor ◽  
Genes Encoding ◽  
Key Enzyme ◽  
Indoleamine Metabolism

Although the regulation of vitellogenesis in insects has been mainly discussed in terms of ‘classical’ lipid hormones, juvenile hormone (JH), and 20-hydroxyecdysone (20E), recent data support the notion that this process must be adjusted in harmony with a nutritional input/reservoir and involvement of certain indoleamines and neuropeptides in regulation of such process. This study focuses on crosstalks among these axes, lipid hormones, monoamines, and neuropeptides in regulation of vitellogenesis in the American cockroach Periplaneta americana with novel aspects in the roles of arylalkylamine N-acetyltransferase (aaNAT), a key enzyme in indoleamine metabolism, and the enteroendocrine peptides; crustacean cardioactive peptide (CCAP) and short neuropeptide F (sNPF). Double-stranded RNA against aaNAT (dsRNAaaNAT) was injected into designated-aged females and the effects were monitored including the expressions of aaNAT itself, vitellogenin 1 and 2 (Vg1 and Vg2) and the vitellogenin receptor (VgR) mRNAs, oocyte maturation and changes in the hemolymph peptide concentrations. Effects of peptides application and 20E were also investigated. Injection of dsRNAaaNAT strongly suppressed oocyte maturation, transcription of Vg1, Vg2, VgR, and genes encoding JH acid- and farnesoate O-methyltransferases (JHAMT and FAMeT, respectively) acting in the JH biosynthetic pathway. However, it did not affect hemolymph concentrations of CCAP and sNPF. Injection of CCAP stimulated, while sNPF suppressed oocyte maturation and Vgs/VgR transcription, i.e., acting as allatomedins. Injection of CCAP promoted, while sNPF repressed ecdysteroid (20E) synthesis, particularly at the second step of Vg uptake. 20E also affected the JH biosynthetic pathway and Vg/VgR synthesis. The results revealed that on the course of vitellogenesis, JH- and 20E-mediated regulation occurs downstream to indoleamines- and peptides-mediated regulations. Intricate mutual interactions of these regulatory routes must orchestrate reproduction in this species at the highest potency.

scholarly journals Functional Analysis of Genes for Biosynthesis of Pyocyanin and Phenazine-1-Carboxamide from Pseudomonas aeruginosa PAO1

2001 ◽  
Vol 183 (21) ◽  
pp. 6454-6465 ◽  
Author(s):  
Dmitri V. Mavrodi ◽  
Robert F. Bonsall ◽  
Shannon M. Delaney ◽  
Marilyn J. Soule ◽  
Greg Phillips ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Biosynthetic Pathway ◽  
Control Synthesis ◽  
Pseudomonas Chlororaphis ◽  
Pseudomonas Aeruginosa Pao1 ◽  
Pseudomonas Aureofaciens ◽  
Functional Studies ◽  
Genes Encoding ◽  
Subsequent Conversion ◽  
Single Compound

ABSTRACT Two seven-gene phenazine biosynthetic loci were cloned fromPseudomonas aeruginosa PAO1. The operons, designatedphzA1B1C1D1E1F1G1 and phzA2B2C2D2E2F2G2, are homologous to previously studied phenazine biosynthetic operons from Pseudomonas fluorescens and Pseudomonas aureofaciens. Functional studies of phenazine-nonproducing strains of fluorescent pseudomonads indicated that each of the biosynthetic operons from P. aeruginosa is sufficient for production of a single compound, phenazine-1-carboxylic acid (PCA). Subsequent conversion of PCA to pyocyanin is mediated in P. aeruginosa by two novel phenazine-modifying genes,phzM and phzS, which encode putative phenazine-specific methyltransferase and flavin-containing monooxygenase, respectively. Expression of phzS alone inEscherichia coli or in enzymes, pyocyanin-nonproducingP. fluorescens resulted in conversion of PCA to 1-hydroxyphenazine. P. aeruginosa with insertionally inactivated phzM or phzS developed pyocyanin-deficient phenotypes. A third phenazine-modifying gene,phzH, which has a homologue in Pseudomonas chlororaphis, also was identified and was shown to control synthesis of phenazine-1-carboxamide from PCA in P. aeruginosa PAO1. Our results suggest that there is a complex pyocyanin biosynthetic pathway in P. aeruginosaconsisting of two core loci responsible for synthesis of PCA and three additional genes encoding unique enzymes involved in the conversion of PCA to pyocyanin, 1-hydroxyphenazine, and phenazine-1-carboxamide.

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