The terminal carbohydrate residues of the N-glycan on the immunoglobulin G (IgG) Fragment crystalizable (Fc) determine whether IgG activates pro- or anti-inflammatory receptors. The IgG Fc alone becomes potently anti-inflammatory upon addition of α2-6 linked N-acetylneuraminic acid residues to the N-glycan, stimulating interest in use of this entity in novel ...

The use of cellulases remains a major cost in the production of renewable fuels and chemicals from lignocellulosic biomass. Fungi secrete copper-dependent polysaccharide monooxygenases (PMOs) that oxidatively cleave crystalline cellulose and improve the effectiveness of cellulases. However, the means by which PMOs recognize and cleave their substrates in the plant ...

The pH-modified citrus pectin (MCP) has been demonstrated to inhibit galectin-3 in cancer progression. The components and structures of MCP related to this inhibition remained unknown. In this paper, we fractionated MCP on DEAE-cellulose column into a homogenous neutral fraction MCP-N (about 20 kDa) and a pectin mixture fraction MCP-A (wide ...

ABSTRACT: Backgrounds Gastroesophageal reflux disease (GERD) is a very common disorder worldwide, comprised of reflux esophagitis (RE) and non-erosive reflux disease (NERD). As more than half of GERD patients are classified into NERD, precise evaluation of bothersome epigastric symptoms is essential. Nevertheless, compared with many reports targeting endoscopic reflux esophagitis, ...

The effects of xylo-oligosaccharides (XOS) and xylose on the hydrolytic activities of cellulases, endoglucanase II (EGII, originating from Thermoascus aurantiacus), cellobiohydrolase I (CBHI, from T. aurantiacus), and cellobiohydrolase II (CBHII, from Trichoderma reesei) on Avicel and nanocellulose were investigated. After the addition of XOS, the amounts of cellobiose, the main ...

Retrograded amylose is resistant to digestion by amylolytic enzymes, which is known as resistant starch type III (RS3). This study investigated the effect of beta-amylase hydrolysis on the formation and physicochemical properties of RS3 from debranched corn starches. Three types of corn starch (Hylon VII, Hylon V, and common corn) ...

In an effort to compare the persistence of imidacloprid and beta-cyfluthrin, when applied through a ready mix formulation, Solomon 300 OD @ 200 and 400 mL ha(-1) in the fruits of brinjal, tomato and okra, the present study has been made. The study indicated that the dissipation of these insecticides irrespective of ...

In order to evaluate the proposed biosynthetic pathway for the methylmannose (MMPs) polysaccharides produced by mycobacteria, two homologous series of synthetic α-(1→4)-linked 3-O-methyl-mannopyranosides, one terminated at the non-reducing end by a free mannopyranose residue (unmethylated oligosaccharides; OS) and the other terminated by a 3-O-methyl-mannopyranose residue (methylated OS), were prepared and ...

A computational investigation has been undertaken to study the hydrolysis of two methyl septanosides, methyl-alpha-D-glycero-D-guloseptanoside and methyl-beta-D-glycero-D-guloseptanoside. The two septanosides were chosen because they were model methyl septanosides for comparison to methyl pyranosides. Also, they allowed comparison of alpha versus beta hydrolysis rates for a specific septanoside isomer. The results ...

Fucosylated alpha-fetoprotein (AFP) is a more specific biomarker for hepatocellular carcinoma (HCC) than AFP. However, the mechanisms underlying the increase in fucosylated AFP in sera of HCC patients remain largely unknown. Recently, we reported that fucosylation is a possible signal for the secretion of hepatic glycoproteins into bile and that ...

The degradation of the plant cell wall by glycoside hydrolases is central to environmentally sustainable industries. The major polysaccharides of the plant cell wall are cellulose and xylan, a highly decorated β-1,4-xylopyranose polymer. Glycoside hydrolases displaying multiple catalytic functions may simplify the enzymes required to degrade plant cell walls, increasing ...

Natural N-glycosylation involves a β-anomeric linkage connecting the sugar to one asparagine residue of the protein. We herein report NMR- and modelling-based data on glycomimetics containing α-glycosidic linkages. The bioactivity of α-Gal-containing glycopeptides has been documented by revealing binding to two plant lectins, i.e. a potent β-trefoil toxin (Viscum album ...

BACKGROUND: The aim is to analyze the structure, anticoagulant and antithrombotic activities of a sulfated fucan isolated from sea cucumber Isostichopus badionotus (fucan-Ib). METHODS: Fucan-Ib was hydrolyzed under mild acid conditions. The oligosaccharide fragments were fractionated by gel-filtration chromatography and the structures were determined by negative-ion electrospray tandem mass spectrometry ...

Beta-carotene (BC) is the major dietary source of provitamin A. Central cleavage of BC catalyzed by beta-carotene oxygenase 1 yields two molecules of retinaldehyde. Subsequent oxidation produces all-trans retinoic acid (ATRA) which functions as a ligand for a family of nuclear transcription factors, the retinoic acid receptors (RARs). Eccentric cleavage ...

A low molecular weight fraction, designated LMWP, was prepared by mild acid hydrolysis of sulfated rhamnan from Monostroma latissimum and purified by anion-exchange and gel-permeation chromatography. Chemical and spectroscopic analyses showed that LMWP was mainly composed of rhamnose, and its molecular weight was about 33.6kDa. The backbone of LMWP consists ...

Glycosaminoglycans [GAGs] are essential heteropolysaccharides in vertebrate tissues that are also, in certain cases, employed as virulence factors by microbes. Hyaluronan [HA], heparin, and chondroitin sulfate [CS] are GAGs currently used in various medical applications and together are multi-billion dollar products thus targets for production by animal-free manufacture. By using ...

The O-polysaccharide (O-PS; O-antigen) of bacterial lipopolysaccharides is made up of repeating units of one or more sugar residues and displays remarkable structural diversity. Despite the structural variations, there are only three strategies for O-PS assembly. The ATP-binding cassette (ABC)-transporter-dependent mechanism of O-PS biosynthesis is widespread. The Escherichia coli O9a ...

Agars are abundant polysaccharides from marine red algae and their chemical structure consists of alternating D- galactose and 3,6-anhydro-L-galactose residues, the latter of which is presumed to make the polymer recalcitrant to degradation by most terrestrial bacteria. Here we study a family 117 glycoside hydrolase (BpGH117) encoded within a recently ...

Mammalian milk or colostrum contains up to 10% of carbohydrate, of which free lactose usually constitutes more than 80%. Lactose is synthesized within lactating mammary glands from uridine diphosphate galactose (UDP-Gal) and glucose by a transgalactosylation catalysed by a complex of β4-galactosyltransferase and α-lactalbumin (α-LA). α-LA is believed to have ...

Endo-β-N-acetylglucosaminidases (ENGases) are widely used to remove N-linked oligosaccharides from glycoproteins for glycomic and proteomic studies and biopharmaceutical processes. Although several ENGases are widely available and their main oligosaccharide structural preferences are generally known (i.e. high mannose, hybrid or complex), the preferences of ENGases from different kingdoms for individual structural ...

The rice BGlu1 β-d-glucosidase nucleophile mutant E386G is a glycosynthase that catalyzes the synthesis of cellooligosaccharides from α-d-glucopyranosyl fluoride (GlcF) donor and p-nitrophenyl (pNP) cellobioside (Glc2-pNP) or cello-oligosaccharide acceptors. When activity with other donors and acceptors was tested, the initial enzyme preparation cleaved pNP-β-d-glucopyranoside (Glc-pNP) and pNP-β-d-fucopyranoside (Fuc-pNP) to pNP ...

ABSTRACT: BACKGROUND: Recently, the increased demand of energy has strongly stimulated the research on the conversion of lignocellulosic biomass into reducing sugars for the subsequent production, and beta-glucosidases have been the focus because of their important roles in a variety fundamental biological processes and the synthesis of useful beta-glucosides. Although ...

Agonist-induced lipolysis of adipose fat is robustly inhibited by insulin or by feedback inhibition by the long-chain fatty acids (LCFA) produced during lipolysis. However, the mode of action of LCFA in suppressing adipose lipolysis is not clear. [beta][beta]'-Tetramethyl hexadecanedioic acid (M[beta][beta]/MEDICA16) is a synthetic LCFA that is neither esterified into ...

Endo-D is an endoglycosidase capable of hydrolyzing the Fc N-glycan of intact IgG antibodies after sequential removal of the sialic acid, galactose, and internal GlcNAc residues in the N-glycan. Endo-D also possesses transglycosylation activity with sugar oxazoline as the donor substrate, but the transglycosylation yield is low due to enzymatic ...

Parkinson's disease is an aged-related movement disorder characterized by the presence in the mid-brain of amyloid deposits of the 140-aa protein alpha-synuclein (AS). AS fibrillation follows a nucleation polymerization pathway involving diverse transient prefibrillar species varying in size and morphology. Like for other neurodegenerative diseases, cytotoxicity is currently attributed to ...

The structure of quinol-dependent nitric oxide reductase (qNOR) from G. stearothermophilus, which catalyzes the reduction of NO to produce the major ozone-depleting gas N(2)O, has been characterized at 2.5 Å resolution. The overall fold of qNOR is similar to that of cytochrome c-dependent NOR (cNOR), and some structural features that ...

Crystal structures of toluene 4-monooxygenase hydroxylase in complex with reaction products and effector protein reveal active site interactions leading to regiospecificity. Complexes with phenolic products yield an asymmetric µ-phenoxo bridged diiron center and a shift of diiron ligand E231 into a hydrogen bonding position with conserved T201. In contrast, complexes ...

Although various T. vivax purine-specific inosine-adenosine-guanosine nucleoside hydrolase (IAG-NH) crystal structures were determined in recent years, the mechanistic details for the cleavage of N-glycosidic bond and the release of base are still unclear. Herein the irreversible hydrolysis reaction has been studied by ab initio QM/MM MD simulations, and the results ...

Cytochrome c assembly requires sulfhydryls at the CXXCH heme-binding site on the apoprotein and also chemical reduction of the heme co-factor. In yeast mitochondria, the cytochrome heme lyases (CCHL, CC(1) HL) and Cyc2p catalyze covalent heme attachment to apocytochromes c and c(1) . An in vivo indication that Cyc2p controls ...

The ATP synthase is the key player of Mitchell's chemiosmotic theory, converting the energy of transmembrane proton flow into the high-energy bond between ADP and phosphate. The proton motive force that drives this reaction consists of two components, the pH difference (ΔpH) across the membrane and transmembrane electrical potential (Δψ). ...

Protease-catalyzed hydrolysis of peptide bonds is one of the most pivotal posttranslational modifications fulfilling manifold functions in the regulation of cellular processes. Therefore, dysregulation of proteolytic reactions plays a central role in many pathophysiological events. For this reason, the understanding of the molecular mechanisms in proteolytic reactions, in particular the ...

Proteolysis is the key step for proteomic studies integrated with MS analysis. Compared with the conventional method of in-solution digestion, proteolysis by a protease-immobilized microreactor has a number of advantages for proteomic analysis; i.e., rapid and efficient digestion, elimination of a purification step of the digests prior to MS, and ...

Rho GTPases act as tightly regulated molecular switches governing a large variety of critical cellular functions. Their activity is controlled by two different biochemical reactions, the GDP/GTP exchange and the GTP hydrolysis. These very slow reactions require catalysis in cells by two kinds of regulatory proteins. While the guanine nucleotide ...

SNARE complexes are required for membrane fusion in the endomembrane system. They contain coiled-coil bundles of four helices, three (Q(a), Q(b), and Q(c)) from target (t)-SNAREs and one (R) from the vesicular (v)-SNARE. NSF/Sec18 disrupts these cis-SNARE complexes, allowing reassembly of their subunits into trans-SNARE complexes and subsequent fusion. Studying ...

Marine sulfated polysaccharides (MSPs), such as sulfated fucans (SFs), sulfated galactans (SGs), and glycosaminoglycans (GAGs) isolated from invertebrate animals, are highly anionic polysaccharides capable of interacting with certain cationic proteins, such as (co)-factors of the coagulation cascade during clotting-inhibition process. Primarily, these molecular complexes between MSPs and coagulation-related proteins seem ...

The aerotolerant anaerobe Streptococcus pneumoniae is part of the normal nasopharyngeal microbiota of humans and one of the most important invasive pathogens. A genomic survey allowed establishing the occurrence of twenty-one phosphotransferase systems, seven carbohydrate uptake ABC transporters, one sodium∶solute symporter and a permease, underlining an exceptionally high capacity for ...

Human milk and colostrum contain ∼12-13 g/L and ∼22-24 g/L of oligosaccharides, respectively. The chemical structures of >100 human milk oligosaccharides (HMO) have been characterized to date. We determined the concentrations of 10 neutral and 9 acidic colostrum HMO collected during the first 3 d of lactation by using reverse ...

The 4-hydroxybenzoyl-CoA (4-HB-CoA)1 thioesterase from Pseudomonas sp strain CBS3 catalyzes the final step of the 4-chlorobenzoate degradation pathway, which is the hydrolysis of 4-hydroxybenzoyl-CoA (4-HB-CoA) to coenzyme A (CoA) and 4-hydroxybenzoate. In previous work, X-ray structural analysis of the substrate-bound thioesterase provided evidence for the role of an active site ...

The functionally versatile (β/α)(8) barrel scaffold was used to migrate triosephosphate isomerase (TPI) to thiamin phosphate synthase (TPS) activity, two enzymes that share the same fold but catalyze unrelated reactions through different mechanisms. The high sensitivity of the selection methodology was determinant to succeed in finding proteins with the desired ...

Glutathione is an intracellular redox-active tripeptide thiol with a central role in cellular physiology across all kingdoms of life. Glutathione biosynthesis has been traditionally viewed as a conserved process relying on the sequential activity of two separate ligases, but recently, an enzyme (GshF) that unifies both necessary reactions in one ...

Upper hinge is vulnerable to radical attacks that result in breakage of the heavy-light chain linkage and cleavage of the hinge of an IgG1. To further explore mechanisms responsible for the radical induced hinge degradation, nine mutants were designed to determine the roles that the upper hinge Asp and His ...

The V-ATPase of Saccharomyces cerevisiae is an ATP-dependent proton pump responsible for acidification of the vacuole and other internal compartments including the whole secretory pathway. We have studied the behaviour of several glycoprotein processing reactions occurring in different Golgi compartments of representative vmaΔ mutants. We found that outer chain initiation ...

The penultimate reaction in the oxidative degradation of nicotinate (vitamin B(3)) to fumarate in several species of aerobic bacteria is the hydrolytic deamination of maleamate to maleate, catalyzed by maleamate amidohydrolase (NicF). Although it has been considered a model system for bacterial degradation of N-heterocyclic compounds, only recently have gene ...

Protein splicing is a post-translational process in which a biologically inactive protein is activated by the release of a segment denoted as an intein. The process involves four steps. In the third, the scission of the intein takes place after the cyclization of the last amino acid of the segment, ...

Inteins are single-turnover catalysts that splice themselves out of a precursor polypeptide chain. For most inteins, the first step of protein splicing is the formation of a thioester through an N-S acyl shift at the upstream splice junction. However, the mechanism by which this reaction is achieved and the impact ...

Both CYP158A1 and CYP158A2 are able to catalyze an oxidative C-C coupling reaction producing biflaviolin or triflaviolin in Streptomyces coelicolor A3(2). The substrate-bound crystal structures of CYP158A2 and CYP158A1 reveal that the side chain of Ile87 in CYP158A2 points to the active site contacting the distal flaviolin molecule, however, the ...

Ketosynthases produce the carbon backbones of a vast number of biologically active polyketides by catalyzing Claisen condensations of activated acyl and malonyl building blocks. Here we report that a ketosynthase homolog from Streptomyces tendae, CerJ, unexpectedly forms malonyl esters during the biosynthesis of cervimycin, a glycoside antibiotic against methicillin-resistant Staphylococcus ...

Microcystins are cyclic peptides produced by Cyanobacteria that are hepatotoxic to mammals. The toxicity mechanism involves the potent inhibition of protein phosphatases, as the toxins bind the catalytic subunits of five enzymes of the PPP family of serine/threonine-specific phosphatases: Ppp1 (aka PP1), Ppp2 (aka PP2A), Ppp4, Ppp5 and Ppp6. The ...

Here we present the in vitro selection of a novel ribozyme specific for Zn2+-dependent catalysis on hydrolysis of a phosphorothiolate thiolester bond. The ribozyme, called the TW17 ribozyme, was evolved and selected from an artificial RNA pool covalently linked to a biotin-containing substrate through the phosphorothiolate thiolester bond. The secondary ...

Ribokinase is responsible for catalyzing the reaction of d-ribose and ATP to produce ribose-5-phosphate and ADP, which can be activated by monovalent cations such as potassium, cesium and ammonium. However, the exact activation mechanism of ribokinase remains elusive. Here we report the crystal structure of Sa239, a ribokinase from Staphylococcus ...