Entamoeba histolytica: identification of thioredoxin-targeted proteins and analysis of serine acetyltransferase-1 as a prototype example

2013 ◽  
Vol 451 (2) ◽  
pp. 277-288 ◽  
Author(s):  
Sarah Schlosser ◽  
David Leitsch ◽  
Michael Duchêne
Keyword(s):  
Entamoeba Histolytica ◽  
Active Site ◽  
Gel Electrophoresis ◽  
Biosynthetic Pathway ◽  
Interacting Proteins ◽  
Protozoan Parasites ◽  
Serine Acetyltransferase ◽  
Two Dimensional Gel Electrophoresis ◽  
Mixed Disulfide ◽  
Far Western Blot

Entamoeba histolytica, the causative agent of amoebiasis, possesses the dithiol-containing redox proteins Trx (thioredoxin) and TrxR (Trx reductase). Both proteins were found to be covalently modified and inactivated by metronidazole, a 5-nitroimidazole drug that is commonly used to treat infections with microaerophilic protozoan parasites in humans. Currently, very little is known about enzymes and other proteins participating in the Trx-dependent redox network of the parasite that could be indirectly affected by metronidazole treatment. On the basis of the disulfide/dithiol-exchange mechanism we constructed an active-site mutant of Trx, capable of binding interacting proteins as a stable mixed disulfide intermediate to screen the target proteome of Trx in E. histolytica. By applying Trx affinity chromatography, two-dimensional gel electrophoresis and MS, peroxiredoxin and 15 further potentially redox-regulated proteins were identified. Among them, EhSat1 (E. histolytica serine acetyltransferase-1), an enzyme involved in the L-cysteine biosynthetic pathway, was selected for detailed analysis. Binding of Trx to EhSat1 was verified by Far-Western blot analysis. Trx was able to restore the activity of the oxidatively damaged EhSat1 suggesting that the TrxR/Trx system protects sensitive proteins against oxidative stress in E. histolytica. Furthermore, the activity of peroxiredoxin, which is dependent on a functioning TrxR/Trx system, was strongly reduced in metronidazole-treated parasites.

Oxidative modifications of glyceraldehyde-3-phosphate dehydrogenase play a key role in its multiple cellular functions

2009 ◽  
Vol 423 (2) ◽  
pp. 253-264 ◽  
Author(s):  
Na Rae Hwang ◽  
Seung-Hee Yim ◽  
Young Mee Kim ◽  
Jaeho Jeong ◽  
Eun Joo Song ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Active Site ◽  
Gel Electrophoresis ◽  
Rna Binding ◽  
Binding Protein ◽  
Interacting Proteins ◽  
Two Dimensional ◽  
Cellular Functions ◽  
Two Dimensional Gel Electrophoresis ◽  
Polypyrimidine Tract Binding Protein

Knowledge of the cellular targets of ROS (reactive oxygen species) and their regulation is an essential prerequisite for understanding ROS-mediated signalling. GAPDH (glyceraldehyde-3-phosphate dehydrogenase) is known as a major target protein in oxidative stresses and becomes thiolated in its active site. However, the molecular and functional changes of oxidized GAPDH, the inactive form, have not yet been characterized. To examine the modifications of GAPDH under oxidative stress, we separated the oxidation products by two-dimensional gel electrophoresis and identified them using nanoLC-ESI-q-TOF MS/MS (nano column liquid chromatography coupled to electrospray ionization quadrupole time-of-flight tandem MS). Intracellular GAPDH subjected to oxidative stress separated into multiple acidic spots on two-dimensional gel electrophoresis and were identified as cysteine disulfide and cysteic acids on Cys152 in the active site. We identified the interacting proteins of oxidized inactive GAPDH as p54nrb (54 kDa nuclear RNA-binding protein) and PSF (polypyrimidine tract-binding protein-associated splicing factor), both of which are known to exist as heterodimers and bind to RNA and DNA. Interaction between oxidized GAPDH and p54nrb was abolished upon expression of the GAPDH active site mutant C152S. The C-terminal of p54nrb binds to GAPDH in the cytosol in a manner dependent on the dose of hydrogen peroxide. The GAPDH–p54nrb complex enhances the intrinsic topoisomerase I activation by p54nrb–PSF binding. These results suggest that GAPDH exerts other functions beyond glycolysis, and that oxidatively modified GAPDH regulates its cellular functions by changing its interacting proteins, i.e. the RNA splicing by interacting with the p54nrb–PSF complex.

scholarly journals Identification of Proteins Related to Nickel Homeostasis in Helicobater pylori by Immobilized Metal Affinity Chromatography and Two-Dimensional Gel Electrophoresis

2008 ◽  
Vol 2008 ◽  
pp. 1-6 ◽  
Author(s):  
Xuesong Sun ◽  
Ruiguang Ge ◽  
Jen-Fu Chiu ◽  
Hongzhe Sun ◽  
Qing-Yu He
Keyword(s):  
Affinity Chromatography ◽  
Gel Electrophoresis ◽  
Interacting Proteins ◽  
Peptic Ulcers ◽  
Two Dimensional ◽  
Two Dimensional Gel Electrophoresis ◽  
Iron Storage ◽  
Cell Extracts ◽  
Nickel Homeostasis ◽  
H Pylori

Helicobacter pylori (H. pylori) is a widespread human pathogen causing peptic ulcers and chronic gastritis. Maintaining nickel homeostasis is crucial for the establishment of H. pylori infection in humans. We used immobilized-nickel affinity chromatography to isolate Ni-related proteins from H. pylori cell extracts. Two-dimensional gel electrophoresis and mass spectrometry were employed to separate and identify twenty two Ni-interacting proteins in H. pylori. These Ni-interacting proteins can be classified into several general functional categories, including cellular processes (HspA, HspB, TsaA, and NapA), enzymes (Urease, Fumarase, GuaB, Cad, PPase, and DmpI), membrane-associated proteins (OM jhp1427 and HpaA), iron storage protein (Pfr), and hypothetical proteins (HP0271, HP jhp0216, HP jhp0301, HP0721, HP0614, and HP jhp0118). The implication of these proteins in nickel homeostasis is discussed.

scholarly journals Replication initiates at multiple dispersed sites in the ribosomal DNA plasmid of the protozoan parasite Entamoeba histolytica.

1996 ◽  
Vol 16 (5) ◽  
pp. 2314-2324 ◽  
Author(s):  
S K Dhar ◽  
N R Choudhury ◽  
V Mittal ◽  
A Bhattacharya ◽  
S Bhattacharya
Keyword(s):  
Electron Microscopy ◽  
Entamoeba Histolytica ◽  
Gel Electrophoresis ◽  
Protozoan Parasite ◽  
Rrna Genes ◽  
Two Dimensional ◽  
Electron Microscopic ◽  
Two Dimensional Gel Electrophoresis ◽  
Rrna Transcription ◽  
Direct Demonstration

In the protozoan parasite Entamoeba histolytica (which causes amoebiasis in humans), the rRNA genes (rDNA) in the nucleus are carried on an extrachromosomal circular plasmid. For strain HM-1:IMSS, the size of the rDNA plasmid is 24.5 kb, and 200 copies per genome are present. Each circle contains two rRNA transcription units as inverted repeats separated by upstream and downstream spacers. We have studied the replication of this molecule by neutral/neutral two-dimensional gel electrophoresis and by electron microscopy. All restriction fragments analyzed by two-dimensional gel electrophoresis gave signals corresponding to simple Y's and bubbles. This showed that replication initiated in this plasmid at multiple, dispersed locations spread throughout the plasmid. On the basis of the intensity of the bubble arcs, initiations from the rRNA transcription units seemed to occur more frequently than those from intergenic spacers. Multiple, dispersed initiation sites were also seen in the rDNA plasmid of strain HK-9 when it was analyzed by two-dimensional gel electrophoresis. Electron microscopic visualization of replicating plasmid molecules in strain HM-1:IMISS showed multiple replication bubbles in the same molecule. The location of bubbles on the rDNA circle was mapped by digesting with PvuI or BsaHI, which linearize the molecule, and with SacII, which cuts the circle twice. The distance of the bubbles from one end of the molecule was measured by electron microscopy. The data corroborated those from two-dimensional gels and showed that replication bubbles were distributed throughout the molecule and that they appeared more frequently in rRNA transcription units. The same interpretation was drawn from electron microscopic analysis of the HK-9 plasmid. Direct demonstration of more than one bubble in the same molecule is clear evidence that replication of this plasmid initiates at multiple sites. Potential replication origins are distributed throughout the plasmid. Such a mechanism is not known to operate in any naturally occurring prokaryotic or eukaryotic plasmid.

Structure-based mutational studies of O-acetylserine sulfhydrylase reveal the reason for the loss of cysteine synthase complex formation in Brucella abortus

2017 ◽  
Vol 474 (7) ◽  
pp. 1221-1239 ◽  
Author(s):  
Sudhaker Dharavath ◽  
Isha Raj ◽  
Samudrala Gourinath
Keyword(s):  
Surface Plasmon Resonance ◽  
Complex Formation ◽  
Surface Plasmon ◽  
Brucella Abortus ◽  
Active Site ◽  
Cysteine Biosynthesis ◽  
Protozoan Parasites ◽  
Serine Acetyltransferase ◽  
Cysteine Synthase ◽  
Active Site Pocket

Cysteine biosynthesis takes place via a two-step pathway in bacteria, fungi, plants and protozoan parasites, but not in humans, and hence, the machinery of cysteine biosynthesis is an opportune target for therapeutics. The decameric cysteine synthase complex (CSC) is formed when the C-terminal tail of serine acetyltransferase (SAT) binds in the active site of O-acetylserine sulfydrylase (OASS), playing a role in the regulation of this pathway. Here, we show that OASS from Brucella abortus (BaOASS) does not interact with its cognate SAT C-terminal tail. Crystal structures of native BaOASS showed that residues Gln96 and Tyr125 occupy the active-site pocket and interfere with the entry of the SAT C-terminal tail. The BaOASS (Q96A–Y125A) mutant showed relatively strong binding (Kd = 32.4 μM) to BaSAT C-terminal peptides in comparison with native BaOASS. The mutant structure looks similar except that the active-site pocket has enough space to bind the SAT C-terminal end. Surface plasmon resonance results showed a relatively strong (7.3 μM Kd) interaction between BaSAT and the BaOASS (Q96A–Y125A), but no interaction with native BaOASS. Taken together, our observations suggest that the CSC does not form in B. abortus.

Diversity of Glycoprotein Deficiencies in Glanzmann’s Thrombasthenia

1985 ◽  
Vol 54 (03) ◽  
pp. 626-629 ◽  
Author(s):  
M Meyer ◽  
F H Herrmann
Keyword(s):  
High Resolution ◽  
Gel Electrophoresis ◽  
Type Ii ◽  
Two Dimensional ◽  
Two Dimensional Gel Electrophoresis ◽  
Structural Variant ◽  
Glanzmann’S Thrombasthenia ◽  
Crossed Immunoelectrophoresis ◽  
Glanzmann's Thrombasthenia ◽  
Platelet Proteins

SummaryThe platelet proteins of 9 thrombasthenic patients from 7 families were analysed by high resolution two-dimensional gel electrophoresis (HR-2DE) and crossed immunoelectrophoresis (CIE). In 7 patients both glycoproteins (GPs) IIb and Ilia were absent or reduced to roughly the same extent. In two related patients only a trace of GP Ilb-IIIa complex was detected in CIE, but HR-2DE revealed a glycopeptide in the position of GP Ilia in an amount comparable to type II thrombasthenia. This GP Ilia-like component was neither recognized normally by anti-GP Ilb-IIIa antibodies nor labeled by surface iodination. In unreduced-reduced two-dimensional gel electrophoresis two components were observed in the region of GP Ilia. The assumption of a structural variant of GP Ilia in the two related patients is discussed.

Comparative Two-Dimensional Gel Electrophoresis of Trypanosoma cruzi Mammalian-Stage Forms in an Alkaline pH Range

2015 ◽  
Vol 22 (12) ◽  
pp. 1066-1075 ◽  
Author(s):  
Adriana Magalhães ◽  
Rayner Queiroz ◽  
Izabela Bastos ◽  
Jaime Santana ◽  
Marcelo Sousa ◽  
...  
Keyword(s):  
Trypanosoma Cruzi ◽  
Gel Electrophoresis ◽  
Two Dimensional ◽  
Alkaline Ph ◽  
Two Dimensional Gel Electrophoresis ◽  
Ph Range

Proteome Analysis of CD4+ T Cells Reveals Differentially Expressed Proteins in Infertile Polycystic Ovary Syndrome Patients

2020 ◽  
Vol 20 ◽  
Author(s):  
Fatemeh Nasri ◽  
Maryam Zare ◽  
Mehrnoosh Doroudchi ◽  
Behrouz Gharesi-Fard
Keyword(s):  
Mass Spectrometry ◽  
T Cells ◽  
T Lymphocytes ◽  
Gel Electrophoresis ◽  
Cd4 T Cells ◽  
Polycystic Ovary ◽  
Proteome Analysis ◽  
Two Dimensional ◽  
Ovary Syndrome ◽  
Two Dimensional Gel Electrophoresis

Background: Polycystic ovary syndrome (PCOS) is the most frequent endocrine disorder affecting 6–7% of premenopausal women. Recent studies revealed that the immune system especially CD4+ T helper cells are important in the context PCOS. Proteome analysis of CD4+ T lymphocytes can provide valuable information regarding the biology of these cells in the context of PCOS. Objective: To investigate immune dysregulation in CD4+ T lymphocytes at the protein level in the context of PCOS using two-dimensional gel electrophoresis (2DE) and mass spectrometry (MS). Methods: In the present study, we applied two-dimensional gel electrophoresis / mass spectrometry to identify proteins differentially expressed by peripheral blood CD4+ T cells in ten PCOS women compared with ten healthy women. Western blot technique was used to confirm the identified proteins. Results: Despite the overall proteome similarities, there were significant differences in the expression of seven spots between two groups (P <0.05). Three proteins, namely phosphatidylethanolamine-binding protein 1, proteasome activator complex subunit 1 and triosephosphate isomerase 1 were successfully identified by Mass technique and confirmed by western blot. All characterized proteins were over-expressed in CD4+ T cells from patients compared to CD4+ T cells from controls (P <0.05). In-silico analysis suggested that the over-expressed proteins interact with other proteins involved in cellular metabolism especially glycolysis and ferroptosis pathway. Conclusion: These findings suggest that metabolic adjustments in CD4+ T lymphocytes, which is in favor of increased glycolysis and Th2 differentiation are important in the context of PCOS.

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