CONSTITUTION OF AN ARABINOGALACTOMANNAN FROM HONEY

1965 ◽  
Vol 43 (2) ◽  
pp. 421-425 ◽  
Author(s):  
I. R. Siddiqui
Keyword(s):  
Structural Features ◽  
Branched Structure ◽  
Hydrolysis Of ◽  
Molecular Proportion

An arabinogalactomannan isolated from honey consisted of D-mannose, L-arabinose, and D-galactose in molar proportions of 1.0:2.04:4.04 respectively. Electrophoretic and sedimentation results indicated that the arabinogalactomannan was homogeneous. Methylation studies showed a highly branched structure. Hydrolysis of the methylated polysaccharide gave 2,3,4,6-tetra-O-methyl-D-mannose (3 molecular proportions); 2,3,4,6-tetra-O-methyl-D-galactose (2 molecular proportions); 2,3,5-tri-O-methyl-L-arabinose (1 molecular proportion); 2,3,4-tri-O-methyl-D-galactose (6 molecular proportions); 2,3-di-O-methyl-L-arabinose (4 molecular proportions); 2,5-di-O-methyl-L-arabinose (1 molecular proportion); 2,4-di-O-methyl-D-galactose (5 molecular proportions). The general structural features of the arabinogalactomannan are discussed.

THE WATER-SOLUBLE POLYSACCHARIDES OF DERMATOPHYTES: IV. GALACTOMANNANS I FROM TRICHOPHYTON GRANULOSUM, TRICHOPHYTON INTERDIGITALE, MICROSPORUM QUINCKEANUM, TRICHOPHYTON RUBRUM, AND TRICHOPHYTON SCHÖNLEINII

1965 ◽  
Vol 43 (1) ◽  
pp. 30-39 ◽  
Author(s):  
C. T. Bishop ◽  
M. B. Perry ◽  
F. Blank ◽  
F. P. Cooper
Keyword(s):  
Aqueous Solutions ◽  
Copper Complexes ◽  
Trichophyton Rubrum ◽  
Periodate Oxidation ◽  
Structural Features ◽  
Water Soluble ◽  
Major Constituent ◽  
Branch Points ◽  
Terminal Units ◽  
Hydrolysis Of

A group of polysaccharides, called galactomannans I, were precipitated as their insoluble copper complexes from aqueous solutions of the crude polysaccharides obtained from each of the organisms designated in the title. The five galactomannans I were homogeneous under conditions of electrophoresis and ultracentrifugation and had high positive specific rotations. The major constituent monosaccharide was D-mannose; amounts of D-galactose ranged from nil for the polysaccharide from T. rubrum to 13% for that from T. schönleinii. Methylation and hydrolysis of the five galactomannans I yielded varying amounts of the following: 2,3,5,6-tetra-O-methyl-D-galactose (not present in the products from T. rubrum), 2,3,4,6-tetra-O-methyl-D-mannose, 2,3,4-tri-O-methyl-D-mannose, 2,4,6-tri-O-methyl-D-mannose, 3,4-di-O-methyl-D-mannose, and 3,5-di-O-methyl-D-mannose. Periodate oxidation results agreed with the methylation studies. The gross structural features of each galactomannan I appear to be the same, namely, a basic chain of 1 → 6 linked α-D-mannopyranose units for approximately every 22 of which there is a 1 → 3 linked α-D-mannopyranose residue. Branch points occur along the 1 → 6 linked chain at the C2 positions of the D-mannopyranose units and once in every 45 units at the C2 position of a 1 → 6 linked D-mannofuranose residue. The D-galactose in the polysaccharides is present exclusively as non-reducing terminal furanose units; non-reducing terminal units of D-mannopyranose are also present. The variations in the identities and relative amounts of the non-reducing terminal units were the only apparent differences in the gross structural features within this group of polysaccharides.

scholarly journals Structural features of the exocellular polysaccharides of Mycobacterium tuberculosis

1994 ◽  
Vol 297 (2) ◽  
pp. 351-357 ◽  
Author(s):  
A Lemassu ◽  
M Daffé
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Molecular Mimicry ◽  
Degradation Products ◽  
Cell Envelope ◽  
Gel Filtration ◽  
Structural Features ◽  
Two Dimensional ◽  
Phagocytic Cells ◽  
Molecular Masses ◽  
Branched Structure

The cell envelope which surrounds pathogenic mycobacteria is postulated to be a defence barrier against phagocytic cells and its outermost constituents have a tendency to accumulate in the culture medium. The present work demonstrates that the exocellular material of Mycobacterium tuberculosis contains large amounts of polysaccharides with only traces, if any at all, of lipids. Three types of polysaccharides were purified by anion-exchange and gel-filtration chromatography; all were found to be neutral compounds devoid of acyl substituents. They consisted of D-glucan, D-arabino-D-mannan and D-mannan, which were eluted from gel-filtration columns in positions corresponding to molecular masses of 123, 13 and 4 kDa respectively. Their predominant structural features were determined by the characterization of the per-O-methyl derivatives of enzymic, acetolysis and Smith-degradation products and by 1H- and 13C-n.m.r. spectroscopy of the purified polysaccharides, using mono- and two-dimensional homonuclear chemical-shift correlated spectroscopy and two-dimensional heteronuclear (1H/13C) spectroscopy. The glucan which represented up to 90% of the polysaccharides was composed of repeating units of five or six-->4-alpha-D-Glcp-1--> residues and a -->4-alpha-D-Glcp substituted at position 6 with an alpha-D-Glcp, indicating a glycogen-like highly branched structure not related to the so-called polysaccharide-II previously identified in tuberculin. The arabinomannan consisted of a mannan segment composed of a -->6-alpha-D-Man-1--> core substituted at some positions 2 with an alpha-D-Manp. The arabinan termini of the arabinomannan were found to be extensively capped with mannosyl residues. The possibility that these polysaccharides contribute to the persistence of the tubercle bacillus in the macrophage by molecular mimicry is discussed.

STRUCTURE OF THE EXTRACELLULAR POLYSACCHARIDE PRODUCED BY XANTHOMONAS ORYZAE

1962 ◽  
Vol 40 (12) ◽  
pp. 2204-2213 ◽  
Author(s):  
A. Misaki ◽  
S. Kirkwood ◽  
J. V. Scaletti ◽  
F. Smith
Keyword(s):  
Acid Hydrolysis ◽  
Glucuronic Acid ◽  
Periodate Oxidation ◽  
Extracellular Polysaccharide ◽  
Xanthomonas Oryzae ◽  
Sodium Borohydride Reduction ◽  
Glycoside Hydrolysis ◽  
Hydrolysis Of ◽  
Structural Significance ◽  
Molecular Proportion

The extracellular polysaccharide isolated from cultures of Xanthomonas oryzae is composed of D-glucose (5 molecular proportions), D-glucuronic acid (2 molecular proportions), and D-mannose (5 molecular proportions). Acid hydrolysis of this polysaccharide, which contains 0.3% combined pyruvic acid, yields 2-O-β-D-glucopyranosyluronic acid D-mannose, which has been characterized as its crystalline fully methylated β-glycoside. Hydrolysis of the methylated polysaccharide gives 2,3,4,6-tetra-O-methyl-D-mannose (3 molecular proportions), 2,3,4-tri-O-methyl-D-glucuronic acid (1 molecular proportion), 2,3,6-tri-O-methyl-D-glucose (4 molecular proportions), 3,4,6-tri-O-methyl-D-mannose (2 molecular proportions), 2,6-di-O-methyl-D-glucose (3 molecular proportions), 2,3-di-O-methyl-D-glucose (1 molecular proportion). The polyalcohol derived from the polysaccharide by periodate oxidation followed by sodium borohydride reduction gives upon acid hydrolysis glycerol (2 molecular proportions), erythritol (1 molecular proportion), and D-glucose (1 molecular proportion). The general structural significance of these findings is discussed.

Structural features underlying the selective cleavage of a novel exo-type maltose-forming amylase fromPyrococcussp. ST04

2014 ◽  
Vol 70 (6) ◽  
pp. 1659-1668 ◽  
Author(s):  
Kwang-Hyun Park ◽  
Jong-Hyun Jung ◽  
Sung-Goo Park ◽  
Myeong-Eun Lee ◽  
James F. Holden ◽  
...  
Keyword(s):  
Amino Acids ◽  
Molecular Basis ◽  
Amino Acid Sequence Identity ◽  
Structural Features ◽  
Industrial Applications ◽  
Closed Cavity ◽  
Helical Bundles ◽  
Sequence Identity ◽  
Hydrolysis Of ◽  
Potential Use

A novel maltose-forming α-amylase (PSMA) was recently found in the hyperthermophilic archaeonPyrococcussp. ST04. This enzyme shows <13% amino-acid sequence identity to other known α-amylases and displays a unique enzymatic property in that it hydrolyzes both α-1,4-glucosidic and α-1,6-glucosidic linkages of substrates, recognizing only maltose units, in an exo-type manner. Here, the crystal structure of PSMA at a resolution of 1.8 Å is reported, showing a tight ring-shaped tetramer with monomers composed of two domains: an N-domain (amino acids 1–341) with a typical GH57 family (β/α)7-barrel fold and a C-domain (amino acids 342–597) composed of α-helical bundles. A small closed cavity observed in proximity to the catalytic residues Glu153 and Asp253 at the domain interface has the appropriate volume and geometry to bind a maltose unit, accounting for the selective exo-type maltose hydrolysis of the enzyme. A narrow gate at the putative subsite +1 formed by residue Phe218 and Phe452 is essential for specific cleavage of glucosidic bonds. The closed cavity at the active site is connected to a short substrate-binding channel that extends to the central hole of the tetramer, exhibiting a geometry that is significantly different from classical maltogenic amylases or β-amylases. The structural features of this novel exo-type maltose-forming α-amylase provide a molecular basis for its unique enzymatic characteristics and for its potential use in industrial applications and protein engineering.

STEREOCHEMICAL STUDIES: V. REARRANGEMENTS ACCOMPANYING ATTEMPTS TO EPIMERIZE 4-OXA-3-OXO-5α-CHOLESTANE AND 4-OXA-3-OXO-5β-CHOLESTANE BY BREWSTER AND KUCERA'S METHOD

1966 ◽  
Vol 44 (3) ◽  
pp. 279-295 ◽  
Author(s):  
W. H. Lunn ◽  
J. T. Edward ◽  
Seymour Meyerson
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Structural Features ◽  
Ring Structure ◽  
Skeletal Rearrangement ◽  
Nuclear Magnetic Resonance Spectra ◽  
Highly Sensitive ◽  
Hydrolysis Of ◽  
Magnetic Resonance Spectra ◽  
Nuclear Magnetic

Epimerization of 4-oxa-3-oxo-5α-cholestane by Brewster and Kucera's method gave only a 23% yield of the 5β-lactone; several other compounds were formed, apparently via skeletal rearrangement during hydrolysis of the tosylate. The attempted epimerization of 4-oxa-3-oxo-5β-cholestane gave mainly unsaturated acids, but no 5α-lactone (a small amount of skeletal rearrangement also occurred). Both epimers undergo rearrangement to γ-lactones when treated with trifluoroacetic acid.Mass spectra, used in conjunction with infrared and nuclear magnetic resonance spectra and other data to make structural assignments, were found to be highly sensitive to certain structural features. In particular, they can usually distinguish sharply between molecules that contain a pendant ring structure and those that do not.

scholarly journals Unravelling the diversity of glycoside hydrolase family 13 α-amylases from Lactobacillus plantarum WCFS1

2019 ◽  
Vol 18 (1) ◽  
Author(s):  
Laura Plaza-Vinuesa ◽  
Oswaldo Hernandez-Hernandez ◽  
F. Javier Moreno ◽  
Blanca de las Rivas ◽  
Rosario Muñoz
Keyword(s):  
Lactobacillus Plantarum ◽  
Glycoside Hydrolase ◽  
Catalytic Efficiency ◽  
Hydrolytic Activity ◽  
Structural Features ◽  
Biochemical Properties ◽  
Glycoside Hydrolase Family ◽  
Reaction Conditions ◽  
Genes Encoding ◽  
Hydrolysis Of

Abstract Background α-Amylases specifically catalyse the hydrolysis of the internal α-1, 4-glucosidic linkages of starch. Glycoside hydrolase (GH) family 13 is the main α-amylase family in the carbohydrate-active database. Lactobacillus plantarum WCFS1 possesses eleven proteins included in GH13 family. Among these, proteins annotated as maltose-forming α-amylase (Lp_0179) and maltogenic α-amylase (Lp_2757) were included. Results In this study, Lp_0179 and Lp_2757 L. plantarum α-amylases were structurally and biochemically characterized. Lp_2757 displayed structural features typical of GH13_20 subfamily which were absent in Lp_0179. Genes encoding Lp_0179 (Amy2) and Lp_2757 were cloned and overexpressed in Escherichia coli BL21(DE3). Purified proteins showed high hydrolytic activity on pNP-α-D-maltopyranoside, being the catalytic efficiency of Lp_0179 remarkably higher. In relation to the hydrolysis of starch-related carbohydrates, Lp_0179 only hydrolysed maltopentaose and dextrin, demonstrating that is an exotype glucan hydrolase. However, Lp_2757 was also able to hydrolyze cyclodextrins and other non-cyclic oligo- and polysaccharides, revealing a great preference towards α-1,4-linkages typical of maltogenic amylases. Conclusions The substrate range as well as the biochemical properties exhibited by Lp_2757 maltogenic α-amylase suggest that this enzyme could be a very promising enzyme for the hydrolysis of α-1,4 glycosidic linkages present in a broad number of starch-carbohydrates, as well as for the investigation of an hypothetical transglucosylation activity under appropriate reaction conditions.

scholarly journals Bordetella holmesii Lipopolysaccharide Hide and Seek Game with Pertussis: Structural Analysis of the O-Specific Polysaccharide and the Core Oligosaccharide of the Type Strain ATCC 51541

2020 ◽  
Vol 21 (17) ◽  
pp. 6433
Author(s):  
Karolina Ucieklak ◽  
Sabina Koj ◽  
Tomasz Niedziela
Keyword(s):  
Whooping Cough ◽  
13C Nmr Spectroscopy ◽  
Structural Features ◽  
The Novel ◽  
Core Oligosaccharide ◽  
The Core ◽  
Sds Page ◽  
Specific Polysaccharide ◽  
First Time ◽  
Hydrolysis Of

Whooping cough is a highly contagious disease caused predominantly by Bordetella pertussis, but it also comprises of a pertussis-like illness caused by B. holmesii. The virulence factors of B. holmesii and their role in the pathogenesis remain unknown. Lipopolysaccharide is the main surface antigen of all Bordetellae. Data on the structural features of the lipopolysaccharide (LPS) of B. holmesii are scarce. The poly- and oligosaccharide components released by mild acidic hydrolysis of the LPS were separated and investigated by 1H and 13C NMR spectroscopy, mass spectrometry, and chemical methods. The structures of the O-specific polysaccharide and the core oligosaccharide of B. holmesii ATCC 51541 have been identified for the first time. The novel pentasaccharide repeating unit of the B. holmesii O-specific polysaccharide has the following structure: {→2)-α-l-Rhap-(1→6)-α-d-Glcp-(1→4)-[β-d-GlcpNAc-(1→3]-α-d-Galp-(1→3)-α-d-GlcpNAc-(1→}n. The SDS-PAGE and serological cross-reactivities of the B. holmesii LPS suggested the similarity between the core oligosaccharides of B. holmesii ATCC 51541 and B. pertussis strain 606. The main oligosaccharide fraction contained a nonasaccharide. The comparative analysis of the NMR spectra of B. holmesii core oligosaccharide fraction with this of the B. pertussis strain 606 indicated that the investigated core oligosaccharides were identical.

Some structural features of the heteropolysaccharides of Candida bogoriensis

1968 ◽  
Vol 46 (21) ◽  
pp. 3407-3411 ◽  
Author(s):  
P. A. J. Gorin ◽  
J. F. T. Spencer
Keyword(s):  
Main Chain ◽  
Glucuronic Acid ◽  
Structural Features ◽  
Side Chain ◽  
Partial Hydrolysis ◽  
Exocellular Polysaccharides ◽  
Hydrolysis Of

The two exocellular polysaccharides of Candida bogoriensis contain D-mannose, D-fucose, L-rhamnose, D-glucuronic acid, and D-galactose residues. The main heteropolymer (> 80%) has an α-D-(1 → 3)-linked mannan main-chain as shown by successive Smith degradations. Partial hydrolysis of the heteropolymers provided several methylpentose-containing oligosaccharide fragments corresponding to possible side-chain components.

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