ArticlePlant molecular biology2012
Site-directed mutagenesis of a tetrameric dandelion polyphenol oxidase (PPO-6) reveals the site of subunit interaction.
Article in Plant molecular biology, 2012. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 12 papers.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
12 citing papers in PubMed, 21 citations in OpenAlex.
- Tyrosinases: a family of copper-containing metalloenzymes.Chemtexts · 2024Article
- Similar but Still Different: Which Amino Acid Residues Are Responsible for Varying Activities in Type-III Copper Enzymes?Chembiochem : a European journal of chemical biology · 2021Review
- Phenoloxidases in Plants-How Structural Diversity Enables Functional Specificity.Frontiers in plant science · 2021Review
- A specific amino acid residue in the catalytic site of dandelion polyphenol oxidases acts as 'selector' for substrate specificity.Plant molecular biology · 2018Article
- Three recombinantly expressed apple tyrosinases suggest the amino acids responsible for mono- versus diphenolase activity in plant polyphenol oxidases.Scientific reports · 2017Article
- Oxidative discolouration in whole-head and cut lettuce: biochemical and environmental influences on a complex phenotype and potential breeding strategies to improve shelf-life.Euphytica: Netherlands journal of plant breeding · 2017Article
- Latent and active aurone synthase from petals of C. grandiflora: a polyphenol oxidase with unique characteristics.Planta · 2015Article
- Site-directed mutagenesis around the CuA site of a polyphenol oxidase from Coreopsis grandiflora (cgAUS1).FEBS letters · 2015Article
- Cloning and functional expression in E. coli of a polyphenol oxidase transcript from Coreopsis grandiflora involved in aurone formation.FEBS letters · 2014Article
- Article
- Article
- Parameters that enhance the bacterial expression of active plant polyphenol oxidases.PloS one · 2013Article
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
3 authors at 2 institutions in 2 countries.
Funding
No grant is acknowledged in the PubMed record.
Abstract
Polyphenol oxidases (PPOs) catalyze the oxidation of ortho-diphenols to the corresponding quinones (EC 1.10.3.1). In plants PPOs appear in gene families, and the corresponding isoenzymes are located to the thylakoid lumen of chloroplasts. Although plant PPOs are often discussed with regard to their role in defense reactions, a common physiological function has not yet been defined. We analyzed a tetrameric PPO isoenzyme (PPO-6) from dandelion (Taraxacum officinale) heterologously expressed in Escherichia coli, and found it to display cooperativity in catalysis, a phenomenon that has rarely been shown for plant PPOs previously. The identification of a surface-exposed cysteine (197) through molecular modeling followed by site-directed mutagenesis proved this amino acid residue to stabilize the tetramer via a disulfide linkage. The C197S-mutein still forms a tetrameric structure but shows impaired enzymatic efficiency and cooperativity and a reduction in stability. These findings indicate that oligomerization may be a physiological requirement for PPO-6 stability and function in vivo and raise new questions regarding distinct functions for specific PPO isoenzymes in plants.
Indexed as
Identifiers
What OpenQuestion holds
Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.