scholarly journals In Vitro Characterization and Concerted Function of Three Core Enzymes of a Glycyl Radical Enzyme - Associated Bacterial Microcompartment

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Jan Zarzycki ◽  
Markus Sutter ◽  
Niña Socorro Cortina ◽  
Tobias J. Erb ◽  
Cheryl A. Kerfeld
Keyword(s):  
Bacterial Microcompartment ◽  
Glycyl Radical ◽  
In Vitro Characterization ◽  
Glycyl Radical Enzyme

scholarly journals A glycyl radical enzyme enables hydrogen sulfide production by the human intestinal bacteriumBilophila wadsworthia

2019 ◽  
Vol 116 (8) ◽  
pp. 3171-3176 ◽  
Author(s):  
Spencer C. Peck ◽  
Karin Denger ◽  
Anna Burrichter ◽  
Stephania M. Irwin ◽  
Emily P. Balskus ◽  
...  
Keyword(s):  
Hydrogen Sulfide ◽  
Bond Cleavage ◽  
Anaerobic Respiration ◽  
Desulfovibrio Desulfuricans ◽  
Intestinal Bacteria ◽  
Differential Proteomics ◽  
Terminal Electron Acceptor ◽  
Glycyl Radical ◽  
Glycyl Radical Enzyme

Hydrogen sulfide (H2S) production in the intestinal microbiota has many contributions to human health and disease. An important source of H2S in the human gut is anaerobic respiration of sulfite released from the abundant dietary and host-derived organic sulfonate substrate in the gut, taurine (2-aminoethanesulfonate). However, the enzymes that allow intestinal bacteria to access sulfite from taurine have not yet been identified. Here we decipher the complete taurine desulfonation pathway inBilophila wadsworthia3.1.6 using differential proteomics, in vitro reconstruction with heterologously produced enzymes, and identification of critical intermediates. An initial deamination of taurine to sulfoacetaldehyde by a known taurine:pyruvate aminotransferase is followed, unexpectedly, by reduction of sulfoacetaldehyde to isethionate (2-hydroxyethanesulfonate) by an NADH-dependent reductase. Isethionate is then cleaved to sulfite and acetaldehyde by a previously uncharacterized glycyl radical enzyme (GRE), isethionate sulfite-lyase (IslA). The acetaldehyde produced is oxidized to acetyl-CoA by a dehydrogenase, and the sulfite is reduced to H2S by dissimilatory sulfite reductase. This unique GRE is also found inDesulfovibrio desulfuricansDSM642 andDesulfovibrio alaskensisG20, which use isethionate but not taurine; corresponding knockout mutants ofD. alaskensisG20 did not grow with isethionate as the terminal electron acceptor. In conclusion, the novel radical-based C-S bond-cleavage reaction catalyzed by IslA diversifies the known repertoire of GRE superfamily enzymes and enables the energy metabolism ofB. wadsworthia. This GRE is widely distributed in gut bacterial genomes and may represent a novel target for control of intestinal H2S production.

scholarly journals The Stickland fermentation precursor trans-4-hydroxyproline differentially impacts the metabolism of Clostridioides difficile and commensal Clostridia

2021 ◽  
Author(s):  
Casey M Theriot ◽  
Amber D Reed ◽  
Joshua R Fletcher ◽  
Yue (Yolanda) Huang ◽  
Rajani Thanissery ◽  
...  
Keyword(s):  
Amino Acid ◽  
Gut Microbiota ◽  
Clostridioides Difficile ◽  
Glycyl Radical ◽  
Metabolic Gene Expression ◽  
Hydroxyproline Metabolism ◽  
Mouse Model Of Infection ◽  
Glycyl Radical Enzyme ◽  
Significant Disease

An intact gut microbiota confers colonization resistance against Clostridioides difficile through a variety of mechanisms, likely including competition for nutrients. Recently, proline was identified as an important environmental amino acid that C. difficile uses to support growth and cause significant disease. The ability to dehydrate trans-4-hydroxyproline via the HypD glycyl radical enzyme is widespread amongst gut microbiota, including C. difficile and members of the commensal Clostridia, suggesting that this amino acid is an important nutrient in the host environment. Therefore, we constructed a C. difficile ΔhypD mutant and found that it was modestly impaired in fitness in a mouse model of infection, and was associated with an altered microbiota when compared to mice challenged with the wild type strain. Changes in the microbiota between the two groups were largely driven by members of the Lachnospiraceae family and the Clostridium genus. We found that C. difficile and type strains of three commensal Clostridia had significant alterations to their metabolic gene expression in the presence of trans-4-hydroxyproline in vitro. The proline reductase (prd) genes were elevated in C. difficile, consistent with the hypothesis that trans-4-hydroxyproline is used by C. difficile to supply proline for fermentation. Similar transcripts were also elevated in some commensal Clostridia tested, although each strain responded differently. This suggests that the uptake and utilization of other nutrients by the commensal Clostridia may be affected by trans-4-hydroxyproline metabolism, highlighting how a common nutrient may be a signal to each organism to adapt to a unique niche.

THE ROLE OF POLYETHYLENIMINE IN ENHANCING PERFORMANCE OF GLUTAMATE BIOSENSORS

2018 ◽  
Vol 8 (3) ◽  
pp. 36-41
Author(s):  
Diep Do Thi Hong ◽  
Duong Le Phuoc ◽  
Hoai Nguyen Thi ◽  
Serra Pier Andrea ◽  
Rocchitta Gaia
Keyword(s):  
First Generation ◽  
Good Reproducibility ◽  
Complex Matrices ◽  
Long Term Stability ◽  
In Vitro Characterization ◽  
Glutamate Oxidase

Background: The first biosensor was constructed more than fifty years ago. It was composed of the biorecognition element and transducer. The first-generation enzyme biosensors play important role in monitoring neurotransmitter and determine small quantities of substances in complex matrices of the samples Glutamate is important biochemicals involved in energetic metabolism and neurotransmission. Therefore, biosensors requires the development a new approach exhibiting high sensibility, good reproducibility and longterm stability. The first-generation enzyme biosensors play important role in monitoring neurotransmitter and determine small quantities of substances in complex matrices of the samples. The aims of this work: To find out which concentration of polyethylenimine (PEI) exhibiting the most high sensibility, good reproducibility and long-term stability. Methods: We designed and developed glutamate biosensor using different concentration of PEI ranging from 0% to 5% at Day 1 and Day 8. Results: After Glutamate biosensors in-vitro characterization, several PEI concentrations, ranging from 0.5% to 1% seem to be the best in terms of VMAX, the KM; while PEI content ranging from 0.5% to 1% resulted stable, PEI 1% displayed an excellent stability. Conclusions: In the result, PEI 1% perfomed high sensibility, good stability and blocking interference. Furthermore, we expect to develop and characterize an implantable biosensor capable of detecting glutamate, glucose in vivo. Key words: Glutamate biosensors, PEi (Polyethylenimine) enhances glutamate oxidase, glutamate oxidase biosensors

Sign in / Sign up

Export Citation Format

Share Document