The Bacillus subtilis endospore coat protein CotA shows laccase activity. By using comparative modeling techniques, we were able to derive a model for based on the known x-ray structures of zucchini ascorbate oxidase and Cuprinus cereneus laccase. This contains all structural features laccase, including reactive surface-exposed copper center (T1) two buried centers (T2 T3). Single amino acid substitutions in T1 (H497A, or M502L) did not prevent assembly mutant proteins into alter pattern...

Endospores produced by the Gram-positive soil bacterium Bacillus subtilis are shielded a proteinaceous coat formed over 30 structural components, which self-assemble into lamellar inner and thicker striated electrodense outer coat. The 65-kDa CotA protein is an abundant component of layer. highly thermostable laccase, assembly required for spore resistance against hydrogen peroxide UV light. Here, we report structure at 1.7-Å resolution, as determined x-ray crystallography. This first...

The CotA laccase from the endospore coat of Bacillus subtilis has been crystallized in presence non-catalytic co-oxidant 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonate) (ABTS), and structure was determined using synchrotron radiation. binding site for this adduct is well defined indicates how ABTS, conjunction with laccases, could act as an oxidative mediator toward non-phenolic moieties. In addition, a dioxygen moiety clearly within solvent channel oriented one T3 copper atoms trinuclear center.

Currently, there is increasing interest in assessing the potential of bacterial laccases for industrial and environmental applications especially harsh conditions. The impact textile industry requires novel effective technologies to mitigate presence dyes wastewaters before discharging into environment. Dyes usually remain stable a variety chemicals, light are recalcitrant microbial degradation. Among available biological treatments offer environmentally friendly strategies decolorizing...

Dye-decolorizing peroxidases (DyPs) are a family of microbial heme-containing that show important properties for lignocellulose biorefineries due to their ability oxidize lignin-related compounds. Directed evolution was used improve the efficiency bacterial PpDyP from Pseudomonas putida MET94 phenolic Three rounds random mutagenesis by error-prone PCR ppDyP gene followed high-throughput screening allow identification 6E10 variant showing 100-fold enhanced catalytic (kcat/Km)...

The multi-copper oxidases oxidise substrate molecules by accepting electrons at a mononuclear copper centre and transferring them to trinuclear centre. Dioxygen binds the and, following transfer of four electrons, is reduced two water. precise mechanism this reduction has been unclear, but recent X-ray structural studies using CotA endospore coat protein from Bacillus subtilis have given further insights into principal stages. It proposed that involves binding dioxygen so it sited...

We examined the accumulation of organic solutes under optimum growth conditions in 12 species thermophilic and hyperthermophilic Archaea belonging to Crenarchaeota Euryarchaeota. Pyrobaculum aerophilum, Thermoproteus tenax, Thermoplasma acidophilum, members order Sulfolobales accumulated trehalose. Pyrococcus furiosus di-myo-inositol-1,1(prm1)(3,3(prm1))-phosphate (beta)-mannosylglycerate, Methanothermus fervidus cyclic-2,3-bisphosphoglycerate while only solute detected Pyrodictium occultum...

(sup13)C and (sup1)H nuclear magnetic resonance spectroscopy was used to identify quantify organic solutes accumulated by the hyperthermophilic archaeon Pyrococcus furiosus in response temperature salinity. Di-myo-inositol-phosphate 2-O-(beta)-mannosylglycerate were major these cells. The total intracellular increased significantly either an increase or salinity, but (beta)-mannosylglycerate mainly at high salinities, whereas concentration of di-myo-inositol-phosphate dramatically...

The laccase-catalysed oxidative coupling of substituted aromatic amines is described, extending the scope laccases towards production phenazine and phenoxazinone derivatives.

FAD-dependent pyranose oxidase (POx) and

Abstract Hyperthermophilic (‘superheat-loving’) archaea found in high-temperature environments such as Pyrobaculum aerophilum contain multicopper oxidases (MCOs) with remarkable efficiency for oxidizing cuprous and ferrous ions. In this work, directed evolution was used to expand the substrate specificity of P. McoP organic substrates. Six rounds error-prone PCR DNA shuffling followed by high-throughput screening lead identification a hit variant 220-fold increased ( k cat /K m ) than...

ABSTRACT The effects of salinity and growth temperature on the accumulation intracellular organic solutes were examined by nuclear magnetic resonance spectroscopy (NMR) in Thermococcus litoralis , celer stetteri zilligii (strain AN1). In addition, stage composition medium studied T. . A novel compound identified as β-galactopyranosyl-5-hydroxylysine was detected grown peptone-containing medium. Besides this newly discovered compound, accumulated mannosylglycerate, aspartate, α-glutamate, di-...

The hyperthermophilic marine archaeon Thermococcus litoralis exhibits high-affinity transport activity for maltose and trehalose at 85 degrees C. K(m) was 22 nM, that 17 nM. In cells had been grown on peptone plus yeast extract, the Vmax uptake ranged from 3.2 to 7.5 nmol/min/mg of protein in different cell cultures. Cells without extract did not show significant or uptake. We found compound responsible induction system trehalose. [14C]maltose 100 nM significantly inhibited by glucose,...

ABSTRACT The dairy industry produces large quantities of whey as a by-product cheese production and is increasingly looking for new ways to utilize this waste product. Gellan gum reliably produced by Sphingomonas paucimobilis in growth media containing lactose, significant component whey, carbon source. We studied compared polysaccharide biosynthesis S. ATCC 31461 glucose, lactose (5 30 g/liter), sweet whey. found that altering the medium can markedly affect yield, acyl substitution level,...

The accumulation of intracellular organic solutes was examined in six species the order Thermotogales by nuclear magnetic resonance spectroscopy. newly discovered compounds di-2-O-beta-mannosyl-di-myo-inositol-1,1'(3,3')-phosphate and di-myo-inositol-1,3'-phosphate were identified Thermotoga maritima neapolitana. In latter species, at optimum temperature salinity solute pool composed di-myo-inositol-1,1'(3,3')-phosphate, beta-glutamate, alpha-glutamate addition to...

Laccases are enzymes that couple the oxidation of substrates with reduction dioxygen to water. They simplest members multi-copper oxidases and contain at least two types copper centres; a mononuclear T1 trinuclear includes T3 one T2 ions. Substrate takes place centre whereas oxygen water occurs centre. In this study, CotA laccase from Bacillus subtilis was used as model understand mechanisms taking molecular level, focus in The structures holo-protein oxidised form apo-protein, which has...

In the present study CotA laccase from Bacillus subtilis has been mutated at two hydrophobic residues in vicinity of type 1 copper site. The mutation Leu(386) to an alanine residue appears cause only very subtle alterations properties enzyme indicating minimal changes structure centres. However, replacement Ile(494) by leads significant enzyme. Thus major visible absorption band is upshifted 16 nm 625 and exhibits increased intensity, whereas intensity shoulder approx. 330 decreased a factor...