Glyoxalase I – structure, function and a critical role in the enzymatic defence against glycation

2003 ◽  
Vol 31 (6) ◽  
pp. 1343-1348 ◽  
Author(s):  
P.J. Thornalley
Keyword(s):  
Metal Ion ◽  
Catalytic Mechanism ◽  
Critical Role ◽  
Glyoxalase I ◽  
Water Molecules ◽  
Glyoxalase System ◽  
E Coli ◽  
Antimalarial Agents

Glyoxalase I is part of the glyoxalase system present in the cytosol of cells. The glyoxalase system catalyses the conversion of reactive, acyclic α-oxoaldehydes into the corresponding α-hydroxyacids. Glyoxalase I catalyses the isomerization of the hemithioacetal, formed spontaneously from α-oxoaldehyde and GSH, to S-2-hydroxyacylglutathione derivatives [RCOCH(OH)-SG→RCH(OH)CO-SG], and in so doing decreases the steady-state concentrations of physiological α-oxoaldehydes and associated glycation reactions. Physiological substrates of glyoxalase I are methylglyoxal, glyoxal and other acyclic α-oxoaldehydes. Human glyoxalase I is a dimeric Zn2+ metalloenzyme of molecular mass 42 kDa. Glyoxalase I from Escherichia coli is a Ni2+ metalloenzyme. The crystal structures of human and E. coli glyoxalase I have been determined to 1.7 and 1.5 Å resolution. The Zn2+ site comprises two structurally equivalent residues from each domain – Gln-33A, Glu-99A, His-126B, Glu-172B and two water molecules. The Ni2+ binding site comprises His-5A, Glu-56A, His-74B, Glu-122B and two water molecules. The catalytic reaction involves base-catalysed shielded-proton transfer from C-1 to C-2 of the hemithioacetal to form an ene-diol intermediate and rapid ketonization to the thioester product. R- and S-enantiomers of the hemithioacetal are bound in the active site, displacing the water molecules in the metal ion primary co-ordination shell. It has been proposed that Glu-172 is the catalytic base for the S-substrate enantiomer and Glu-99 the catalytic base for the R-substrate enantiomer; Glu-172 then reprotonates the ene-diol stereospecifically to form the R-2-hydroxyacylglutathione product. By analogy with the human enzyme, Glu-56 and Glu-122 may be the bases involved in the catalytic mechanism of E. coli glyoxalase I. The suppression of α-oxoaldehyde-mediated glycation by glyoxalase I is particularly important in diabetes and uraemia, where α-oxoaldehyde concentrations are increased. Decreased glyoxalase I activity in situ due to the aging process and oxidative stress results in increased glycation and tissue damage. Inhibition of glyoxalase I pharmacologically with specific inhibitors leads to the accumulation of α-oxoaldehydes to cytotoxic levels; cell-permeable glyoxalase I inhibitors are antitumour and antimalarial agents. Glyoxalase I has a critical role in the prevention of glycation reactions mediated by methylglyoxal, glyoxal and other α-oxoaldehydes in vivo.

scholarly journals Metal ion coordination in the E. coli Nudix hydrolase dihydroneopterin triphosphate pyrophosphatase: New clues into catalytic mechanism

PLoS ONE ◽  
2017 ◽  
Vol 12 (7) ◽  
pp. e0180241 ◽  
Author(s):  
Shannon E. Hill ◽  
Elaine Nguyen ◽  
Chiamaka U. Ukachukwu ◽  
Dana M. Freeman ◽  
Stephen Quirk ◽  
...  
Keyword(s):  
Metal Ion ◽  
Catalytic Mechanism ◽  
Nudix Hydrolase ◽  
E Coli

scholarly journals Escherichia coli YigI is a conserved γ-proteobacterial acyl-CoA thioesterase permitting metabolism of unusual fatty acid substrates

2022 ◽  
Author(s):  
Michael Schmidt ◽  
Theresa Proctor ◽  
Rucheng Diao ◽  
Peter L. Freddolino
Keyword(s):  
Escherichia Coli ◽  
Critical Role ◽  
Acidic Environment ◽  
Unusual Fatty Acid ◽  
E Coli ◽  
Chain Acyl ◽  
Domains Of Life ◽  
Shed Light ◽  
Long Chain

Thioesterases play a critical role in metabolism, membrane biosynthesis, and overall homeostasis for all domains of life. In this present study, we characterize a putative thioesterase from Escherichia coli MG1655 and define its role as a cytosolic enzyme. Building on structure-guided functional predictions, we show that YigI is a medium- to -long chain acyl-CoA thioesterase that is involved in the degradation of conjugated linoleic acid (CLA) in vivo, showing overlapping specificity with two previously defined E. coli thioesterases TesB and FadM. We then bioinformatically identify the regulatory relationships that induce YigI expression, which include: an acidic environment, high oxygen availability, and exposure to aminoglycosides. Our findings define a role for YigI and shed light on why the E. coli genome harbors numerous thioesterases with closely related functions.

scholarly journals Heterologous expression of a Glyoxalase I gene from sugarcane confers tolerance to several environmental stresses in bacteria

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5873 ◽  
Author(s):  
Qibin Wu ◽  
Shiwu Gao ◽  
Yong-Bao Pan ◽  
Yachun Su ◽  
Michael P. Grisham ◽  
...  
Keyword(s):  
Abiotic Stresses ◽  
Plasmid Vector ◽  
Stress Conditions ◽  
Glyoxalase I ◽  
Glyoxalase System ◽  
Biotic And Abiotic Stresses ◽  
Expression Plasmid ◽  
Reading Frame ◽  
E Coli ◽  
I Gene

Glyoxalase I belongs to the glyoxalase system that detoxifies methylglyoxal (MG), a cytotoxic by-product produced mainly from triose phosphates. The concentration of MG increases rapidly under stress conditions. In this study, a novel glyoxalase I gene, designated as SoGloI was identified from sugarcane. SoGloI had a size of 1,091 bp with one open reading frame (ORF) of 885 bp encoding a protein of 294 amino acids. SoGloI was predicted as a Ni2+-dependent GLOI protein with two typical glyoxalase domains at positions 28–149 and 159–283, respectively. SoGloI was cloned into an expression plasmid vector, and the Trx-His-S-tag SoGloI protein produced in Escherichia coli was about 51 kDa. The recombinant E. coli cells expressing SoGloI compared to the control grew faster and tolerated higher concentrations of NaCl, CuCl2, CdCl2, or ZnSO4. SoGloI ubiquitously expressed in various sugarcane tissues. The expression was up-regulated under the treatments of NaCl, CuCl2, CdCl2, ZnSO4 and abscisic acid (ABA), or under simulated biotic stress conditions upon exposure to salicylic acid (SA) and methyl jasmonate (MeJA). SoGloI activity steadily increased when sugarcane was subjected to NaCl, CuCl2, CdCl2, or ZnSO4 treatments. Sub-cellular observations indicated that the SoGloI protein was located in both cytosol and nucleus. These results suggest that the SoGloI gene may play an important role in sugarcane’s response to various biotic and abiotic stresses.

scholarly journals Structure of hibernating ribosomes studied by cryoelectron tomography in vitro and in situ

2010 ◽  
Vol 190 (4) ◽  
pp. 613-621 ◽  
Author(s):  
Julio O. Ortiz ◽  
Florian Brandt ◽  
Valério R.F. Matias ◽  
Lau Sennels ◽  
Juri Rappsilber ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Stress Response ◽  
Spatial Organization ◽  
Three Dimensional ◽  
E Coli ◽  
Escherichia Coli Cells ◽  
Three Dimensional Configuration

Ribosomes arranged in pairs (100S) have been related with nutritional stress response and are believed to represent a “hibernation state.” Several proteins have been identified that are associated with 100S ribosomes but their spatial organization has hitherto not been characterized. We have used cryoelectron tomography to reveal the three-dimensional configuration of 100S ribosomes isolated from starved Escherichia coli cells and we have described their mode of interaction. In situ studies with intact E. coli cells allowed us to demonstrate that 100S ribosomes do exist in vivo and represent an easily reversible state of quiescence; they readily vanish when the growth medium is replenished.

scholarly journals On the catalytic mechanism of prokaryotic leader peptidase 1

1992 ◽  
Vol 282 (2) ◽  
pp. 539-543 ◽  
Author(s):  
M T Black ◽  
J G R Munn ◽  
A E Allsop
Keyword(s):  
Catalytic Mechanism ◽  
Serine Proteinase ◽  
Site Directed Mutagenesis ◽  
Cysteine Residues ◽  
Calculated Molecular Mass ◽  
E Coli ◽  
Leader Peptidase ◽  
Mutant Forms ◽  
Thiol Proteinases

The catalytic mechanism of leader peptidase 1 (LP1) of the bacterium Escherichia coli has been investigated by a combination of site-directed mutagenesis, assays of enzyme activity in vivo utilizing a strain of E. coli which has a conditional defect in LP1 activity, and gene cloning. The biological activity of mutant forms of E. coli LP1 demonstrates that this enzyme belongs to a novel class of proteinases. The possibility that LP1 may be an aspartyl proteinase has been excluded on the basis of primary sequence comparison and mutagenesis. Assignment of LP1 to one of the other three recognized classes of proteinases (metalloproteinases, thiol proteinases and the classical serine proteinases) can also be excluded, as it is clearly demonstrated that none of the histidine or cysteine residues within LP1 are required for catalytic activity. The Pseudomonas fluorescens lep gene has been cloned and sequenced and the corresponding amino acid sequence compared with that of E. coli LP1. The E. coli LP1 and P. fluorescens LP1 primary sequences are 50% identical after insertion of gaps. The P. fluorescens LP1 has 39 fewer amino acids, a calculated molecular mass of 31903 Da and functions effectively in vivo in E. coli. None of the cysteine residues and only one of the histidine residues which are present in E. coli LP1 are conserved in sequence position in the P. fluorescens LP1 enzyme. The possibility that LP1 is a novel type of serine proteinase is discussed.

scholarly journals In situ reprogramming of gut bacteria by oral delivery

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Bryan B. Hsu ◽  
Isaac N. Plant ◽  
Lorena Lyon ◽  
Frances M. Anastassacos ◽  
Jeffrey C. Way ◽  
...  
Keyword(s):  
Oral Delivery ◽  
Multidisciplinary Approach ◽  
Gut Bacteria ◽  
Release Mechanism ◽  
Bacterial Gene ◽  
E Coli ◽  
Bacterial Gene Expression ◽  
Bacterial Function

Abstract Abundant links between the gut microbiota and human health indicate that modification of bacterial function could be a powerful therapeutic strategy. The inaccessibility of the gut and inter-connections between gut bacteria and the host make it difficult to precisely target bacterial functions without disrupting the microbiota and/or host physiology. Herein we describe a multidisciplinary approach to modulate the expression of a specific bacterial gene within the gut by oral administration. We demonstrate that an engineered temperate phage λ expressing a programmable dCas9 represses a targeted E. coli gene in the mammalian gut. To facilitate phage administration while minimizing disruption to host processes, we develop an aqueous-based encapsulation formulation with a microbiota-based release mechanism and show that it facilitates oral delivery of phage in vivo. Finally we combine these technologies and show that bacterial gene expression in the mammalian gut can be precisely modified in situ with a single oral dose.

scholarly journals In Vivo Study of Trichoderma-Pathogen-Plant Interactions, Using Constitutive and Inducible Green Fluorescent Protein Reporter Systems

2004 ◽  
Vol 70 (5) ◽  
pp. 3073-3081 ◽  
Author(s):  
Zexun Lu ◽  
Riccardo Tombolini ◽  
Sheridan Woo ◽  
Susanne Zeilinger ◽  
Matteo Lorito ◽  
...  
Keyword(s):  
Green Fluorescent Protein ◽  
Plant Pathogens ◽  
Fluorescent Protein ◽  
Morphological Changes ◽  
Critical Role ◽  
Pythium Ultimum ◽  
Confocal Scanning Laser Microscopy ◽  
Green Fluorescent

ABSTRACT Plant tissue colonization by Trichoderma atroviride plays a critical role in the reduction of diseases caused by phytopathogenic fungi, but this process has not been thoroughly studied in situ. We monitored in situ interactions between gfp-tagged biocontrol strains of T. atroviride and soilborne plant pathogens that were grown in cocultures and on cucumber seeds by confocal scanning laser microscopy and fluorescence stereomicroscopy. Spores of T. atroviride adhered to Pythium ultimum mycelia in coculture experiments. In mycoparasitic interactions of T. atroviride with P. ultimum or Rhizoctonia solani, the mycoparasitic hyphae grew alongside the pathogen mycelia, and this was followed by coiling and formation of specialized structures similar to hooks, appressoria, and papillae. The morphological changes observed depended on the pathogen tested. Branching of T. atroviride mycelium appeared to be an active response to the presence of the pathogenic host. Mycoparasitism of P. ultimum by T. atroviride occurred on cucumber seed surfaces while the seeds were germinating. The interaction of these fungi on the cucumber seeds was similar to the interaction observed in coculture experiments. Green fluorescent protein expression under the control of host-inducible promoters was also studied. The induction of specific Trichoderma genes was monitored visually in cocultures, on plant surfaces, and in soil in the presence of colloidal chitin or Rhizoctonia by confocal microscopy and fluorescence stereomicroscopy. These tools allowed initiation of the mycoparasitic gene expression cascade to be monitored in vivo.

scholarly journals In situ reprogramming of gut bacteria by oral delivery

2020 ◽  
Author(s):  
Bryan B. Hsu ◽  
Isaac N. Plant ◽  
Lorena Lyon ◽  
Frances M. Anastassacos ◽  
Jeffrey C. Way ◽  
...  
Keyword(s):  
Oral Delivery ◽  
Multidisciplinary Approach ◽  
Gut Bacteria ◽  
Release Mechanism ◽  
Bacterial Gene ◽  
E Coli ◽  
Bacterial Gene Expression ◽  
Bacterial Function

AbstractAbundant links between the gut microbiota and human health indicate that the modification of bacterial function could be a powerful therapeutic strategy. The inaccessibility of the gut and inter-connections between gut bacteria and the host make it difficult to precisely target bacterial functions without disrupting the microbiota and/or host physiology. Herein we describe a multidisciplinary approach to modulate the expression of a specific bacterial gene within the gut by oral administration. We first demonstrate that an engineered temperate phage λ expressing a programmable dCas9 represses a targeted E. coli gene in the mammalian gut. To facilitate phage administration while minimizing disruption to host processes, we develop an aqueous-based encapsulation formulation with a microbiota-based release mechanism and show that it facilitates the oral delivery of phage in vivo. Finally we combine these technologies and show that bacterial gene expression in the mammalian gut can be precisely modified in situ with a single oral dose.

scholarly journals Estimation of Growth Rates of Escherichia coli BJ4 in Streptomycin-Treated and Previously Germfree Mice by In Situ rRNA Hybridization

1999 ◽  
Vol 6 (3) ◽  
pp. 434-436 ◽  
Author(s):  
Camilla U. Rang ◽  
Tine Rask Licht ◽  
Tore Midtvedt ◽  
Patricia L. Conway ◽  
Lin Chao ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Animal Models ◽  
Growth Rates ◽  
Treated Mouse ◽  
23S Rrna ◽  
Growth Physiology ◽  
E Coli ◽  
Bacterial Growth Rates

ABSTRACT The growth physiology of Escherichia coli during colonization of the intestinal tract was studied with four animal models: the streptomycin-treated mouse carrying a reduced microflora, the monoassociated mouse with no other microflora than the introduced strain, the conventionalized streptomycin-treated mouse, and the conventionalized monoassociated mouse harboring a full microflora. A 23S rRNA fluorescent oligonucleotide probe was used for hybridization to whole E. coli cells fixed directly after being taken from the animals, and the respective growth rates of E. coli BJ4 in the four animal models were estimated by correlating the cellular concentrations of ribosomes with the growth rate of the strain. The growth rates thus estimated from the ribosomal content ofE. coli BJ4 in vivo did not differ in the streptomycin-treated and the monoassociated mice. After conventionalization there was a slight decrease of the bacterial growth rates in both animal models.

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