Site‐directed mutagenesis around the CuA site of a polyphenol oxidase from <i>Coreopsis grandiflora</i> (<i>cg</i>AUS1)

Kaintz, Cornelia; Mayer, Rupert L.; Jirsa, Franz; Halbwirth, Heidi; Rompel, Annette

doi:10.1016/j.febslet.2015.02.009

Cited by 20 publications

(20 citation statements)

References 55 publications

(139 reference statements)

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“…The role of Cys97 was also analyzed in aurone synthase from Coreopsis grandiflora (cgAUS1). However, in contrast to TyrAo, in cgAUS1, the replacement of Cys97 to Ala affected protein folding and hindered its activity, but did not have any effect on copper binding …”

Section: Copper In the Binding Sitementioning

confidence: 90%

“…), the CuB site exhibits higher conservation than CuA . Biochemical investigations of tyrosinases from different species have shown the involvement of the conserved histidine residues in copper binding …”

Section: The Overall Structure Of Tyrosinasesmentioning

confidence: 99%

“…The crystal structure of variant V218F exhibited a conformational change of Phe218, which allowed the monophenoalse activity to occur, while the decrease in dipehnolase activity was attributed to the suicide inactivation due to the incorrect orientation of a diphenolic substrate . Moreover, when a blocker residue Phe273 was replaced to Ala in cgAUS, the enzyme lost its activity …”

Section: Active Site Shieldingmentioning

confidence: 99%

“…[9][10][11] Biochemical investigations of tyrosinases from different species have shown the involvement of the conserved histidine residues in copper binding. [11][12][13][14] An unusual thioether bond formed between the second histidine residue coordinating CuA and an adjacent cysteine residue was found in CO of sweet potato (IbCO), tyrosinase from Aspergilus oryzae (TyrAo), and mollusc Hc (Octopus and Rapana Hc) but not in tyrosinases from Streptomyces castaneoglobisporus (TyrSc), Bacillus megaterium (TyrBm), mouse, humans, and arthropodan Hc (Lobster and Crab Hc) ( Fig. 1).…”

Section: The Overall Structure Of Tyrosinasesmentioning

confidence: 99%

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Structure–function correlations in tyrosinases

2015

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Tyrosinases are metalloenzymes belonging to the type-3 copper protein family which contain two copper ions in the active site. They are found in various prokaryotes as well as in plants, fungi, arthropods, and mammals and are responsible for pigmentation, wound healing, radiation protection, and primary immune response. Tyrosinases perform two sequential enzymatic reactions: hydroxylation of monophenols and oxidation of diphenols to form quinones which polymerize spontaneously to melanin. Two other members of this family are catechol oxidases, which are prevalent mainly in plants and perform only the second oxidation step, and hemocyanins, which lack enzymatic activity and are oxygen carriers. In the last decade, several structures of plant and bacterial tyrosinases were determined, some with substrates or inhibitors, highlighting features and residues which are important for copper uptake and catalysis. This review summarizes the updated information on structure-function correlations in tyrosinases along with comparison to other type-3 copper proteins.

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Section: Copper In the Binding Sitementioning

confidence: 90%

Section: The Overall Structure Of Tyrosinasesmentioning

confidence: 99%

Section: Active Site Shieldingmentioning

confidence: 99%

Section: The Overall Structure Of Tyrosinasesmentioning

confidence: 99%

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Structure–function correlations in tyrosinases

2015

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“…However, research has also shown that polyphenols exhibit pro-oxidant behavior, and could be a carcinogen or mutagen [12][13][14][15][16][17][18]. It has been reported that factors such as pH value of media, the presence of transition metals, or enzymes [19][20][21][22], and, particularly, the complexity of each individual's digestive system [23][24][25] have profound impact on these contradictory results.…”

Section: Introductionmentioning

confidence: 99%

Genetic Expression Profile Analysis of the Temporal Inhibition of Quercetin and Naringenin on Lactobacillus Rhamnosus GG

Liu¹,

Firrman²

2016

J Prob Health

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Plant polyphenols quercetin and naringenin are considered healthy dietary compounds; however, little is known of their effect on the probiotic Lactobacillus rhamnosus GG (LGG). In this study it was discovered that both quercetin and naringenin produced temporary inhibition of LGG growth, particularly at 8 hours post inoculation, with LGG eventually recovering from this suppression. The observed growth inhibition was regarded as a phenotypic response of LGG to the polyphenols; we hypothesized that the subsequent recovery was due to unknown, underlying genetic factors. The molecular response of LGG to quercetin and naringenin was determined through RNA analysis using the Helicos single molecule sequencing platform. The expression profiles of LGG grown in the presence of either quercetin or naringenin were divergent from each other, with only a few similarities, indicating that these polyphenols inhibit growth through separate mechanisms.LGG treated with quercetin demonstrated upregulation of genes associated with DNA repair and transcriptional regulation, and a decrease in expression of genes involved in metabolism and protein movement through the cell wall.LGG treated with naringenin resulted in an increase of genes associated with metabolism, and a decrease in genes involved in stress response. Results from this study demonstrate that there is a clear interaction between the polyphenols quercetin and naringenin and the probiotic LGG. The RNA expression analysis provides unique insight into the molecular response of LGG to quercetin and naringenin, revealing an identifiable pattern of gene expression.

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Kristallstruktur einer pflanzlichen Tyrosinase aus Walnussblättern: die Bedeutung “substratlenkender Aminosäurereste” für die Enzymspezifität

et al. 2015

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Tyrosinasen und Catecholoxidasen gehçren zur Klasse der Typ-III-Kupferenzyme.F orscher arbeiten seit Jahrzehnten daran, die Monophenolase-/Diphenolase-Spezifität dieser Enzyme auf struktureller Ebene zu erklären und entwickelten dazu eine Hypothese (basierend auf der ersten Catechol-und Tyrosinasestruktur), der zufolge der Grund für das Fehlen von Monophenolase-Aktivität in Catecholoxidasen das strukturell eingeschränkte aktive Zentrum sein kçnnte. Jüngste strukturelle und biochemische Studien an dieser Enzymklasse liefern jedochAnlass zu Zweifeln an dieser Theorie. Hier wird die erste Kristallstruktur einer pflanzlichen Tyrosinase (Juglans regia) präsentiert, anhand derer gezeigt wird, dass die Unterscheidung zwischen Mono-und Diphenolase-Aktivität auf struktureller Ebene nicht durch eine strukturelle Einschränkung des aktiven Zentrums bestimmt wird;vielmehr spielen Aminosäuren, die sich am Eingang zu und innerhalb der zweiten Schale um das aktive Zentrum befinden, eine viel wichtigere Rolle,a ls bisher angenommen.

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Site‐directed mutagenesis around the CuA site of a polyphenol oxidase from Coreopsis grandiflora (cgAUS1)

Cited by 20 publications

References 55 publications

Structure–function correlations in tyrosinases

Structure–function correlations in tyrosinases

Genetic Expression Profile Analysis of the Temporal Inhibition of Quercetin and Naringenin on Lactobacillus Rhamnosus GG

Kristallstruktur einer pflanzlichen Tyrosinase aus Walnussblättern: die Bedeutung “substratlenkender Aminosäurereste” für die Enzymspezifität

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