Browsing by Author "Maged M."

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Molecular adaptations of bacterial mercuric reductase to the hypersaline Kebrit Deep in the Red Sea
(American Society for Microbiology, 2019) Ramadan E.; Maged M.; Hosseiny A.E.; Chambergo F.S.; Setubal J.C.; Dorry H.E.; Department of Biology; School of Sciences and Engineering; The American University in Cairo; New Cairo; Egypt; Escola de Artes Ci�ncias e Humanidades; Universidade de S�o Paulo; S�o Paulo; Brazil; Instituto de Qu�mica; Universidade de S�o Paulo; S�o Paulo; Brazil; Faculty of Pharmacy; Department of Pharmacology and Biochemistry; The British University in Egypt; El-Sherouk City; Egypt; Faculty of Biotechnology; October University for Modern Sciences and Arts; Cairo; Egypt
The hypersaline Kebrit Deep brine pool in the Red Sea is characterized by high levels of toxic heavy metals. Here, we describe two structurally related mercuric reductases (MerAs) from this site which were expressed in Escherichia coli. Sequence similarities suggest that both genes are derived from proteobacteria, most likely the Betaproteobacteria or Gammaproteobacteria. We show that one of the enzymes (K35NH) is strongly inhibited by NaCl, while the other (K09H) is activated in a NaCl-dependent manner. We infer from this difference that the two forms might support the detoxification of mercury in bacterial microorganisms that employ the compatible solutes and salt-in strategies, respectively. Three-dimensional structure modeling shows that all amino acid substitutions unique to each type are located outside the domain responsible for formation of the active MerA homodimer, and the vast majority of these are found on the surface of the molecule. Moreover, K09H exhibits the predominance of acidic over hydrophobic side chains that is typical of halophilic salt-dependent proteins. These findings enhance our understanding of how selection pressures imposed by two environmental stressors have endowed MerA enzymes with catalytic properties that can potentially function in microorganisms that utilize distinct mechanisms for osmotic balance in hypersaline environments. � 2019 American Society for Microbiology. All Rights Reserved.
A novel thermostable and halophilic thioredoxin reductase from the Red Sea Atlantis II hot brine pool
(Public Library of Science, 2019) Badiea E.A.; Sayed A.A.; Maged M.; Fouad W.M.; Said M.M.; Esmat A.Y.; Department of Biochemistry; Faculty of Science; Ain Shams University; Cairo; Egypt; Department of Biology; School of Sciences and Engineering; American University in Cairo; New Cairo; Egypt; Children Cancer Hospital; Cairo; Egypt; Faculty of Biotechnology; October University for Modern Sciences and Arts; 6th October City; Cairo; Egypt
The highly extreme conditions of the lower convective layer in the Atlantis II (ATII) Deep brine pool of the Red Sea make it an ideal environment for the search for novel enzymes that can function under extreme conditions. In the current study, we isolated a novel sequence of a thioredoxin reductase (TrxR) enzyme from the metagenomic dataset established from the microbial community that resides in the lower convective layer of Atlantis II. The gene was cloned, expressed and characterized for redox activity, halophilicity, and thermal stability. The isolated thioredoxin reductase (ATII-TrxR) was found to belong to the high-molecularweight class of thioredoxin reductases. A search for conserved domains revealed the presence of an extra domain (Crp) in the enzyme sequence. Characterization studies of ATIITrxR revealed that the enzyme was halophilic (maintained activity at 4 M NaCl), thermophilic (optimum temperature was 65�C) and thermostable (60% of its activity was retained at 70�C). Additionally, the enzyme utilized NADH in addition to NADPH as an electron donor. In conclusion, a novel thermostable and halophilic thioredoxin reductase has been isolated with a unique sequence that adapts to the harsh conditions of the brine pools making this protein a good candidate for biological research and industrial applications. � 2019 Badiea et al.
Serum sclerostin and irisin as predictive markers for atherosclerosis in Egyptian type II diabetic female patients: A case control study
(Public Library of Science, 2018) Saadeldin M.K.; Elshaer S.S.; Emara I.A.; Maged M.; Abdel-Aziz A.K.; Department of Biochemistry; Faculty of Pharmacy (Girls); Al-Azhar University; Cairo; Egypt; Department of Biochemistry; National Institute of Diabetes and Endocrinology (NIDE); Cairo; Egypt; Faculty of Biotechnology; October University for Modern Sciences and Arts; 6th October City; Cairo; Egypt; Department of Experimental Oncology; European Institute of Oncology; Milan; Italy
Diabetes mellitus represents a major independent risk factor for developing fatal cardiovascular diseases (CVDs) presumably through accelerating atherosclerosis; the underlying cause of most CVDs. Notably, this relative risk is reported to be higher in women than men. Endeavors directed towards identifying novel reliable predictive biomarkers are immensely thereby urged to improve the long-term outcome in these diabetic female patients. Sclerostin (SOST) is a Wnt signaling antagonist whereas irisin is a muscle-derived factor released after exercising which enhances browning of white adipose tissue. Emerging lines of evidence hint at potential crosstalk between them and CVDs. The present study aimed to assess the serum levels of SOST and irisin in Egyptian type 2 diabetic (T2DM) female patients with and without atherosclerosis and explore the possible relationship between both markers and other studied parameters among the studied cohorts. In this case-control study, 69 female subjects were enrolled; 39 type 2 diabetes patients with atherosclerosis (T2DM+ATHR), 22 type 2 diabetes patients without atherosclerosis (T2DM-ATHR) and 8 healthy controls. Their serum levels of SOST and irisin were assessed using ELISA. Significant increase in SOST levels were found in T2DM+ATHR compared to T2DM-ATHR and control (259.9 �17.98 vs. 165.8�13.12 and 142.0�13.31 pg/mL respectively, P0.001). Conversely, irisin levels were significantly lower in T2DM+ATHR (P0.001) and T2DM-ATHR (P0.01) compared to the control group (32.91�2.545 and 58.55�13.19 vs. 473.6�112.7 pg/ mL). Interestingly, significant correlations between the levels of SOST and both irisin and fasting blood glucose were noticed in T2DM+ATHR group (r = 0.3754 and 0.3381 respectively, P0.05). In conclusion, to the best of our knowledge, this study is the first to demonstrate the correlation between SOST and irisin levels in atherosclerotic T2DM female patients implying their potential implication in diabetic cardiovascular pathophysiology and supporting their use as reliable diagnostic/prognostic biomarkers for monitoring and preventing CVDs progression of T2DM female patients. � 2018 Saadeldin et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Thermal stability of a mercuric reductase from the Red Sea Atlantis II hot brine environment as analyzed by site-directed mutagenesis
(American Society for Microbiology, 2019) Maged M.; Hosseiny A.E.; Saadeldin M.K.; Aziz R.K.; Ramadan E.; Department of Biology; School of Sciences and Engineering; The American University in Cairo; New Cairo; Egypt; Department of Microbiology and Immunology; Faculty of Pharmacy; Cairo University; Cairo; Egypt; Faculty of Pharmacy; The British University in Egypt (BUE); El Shorouk; Egypt; Science and Technology Research Center; School of Sciences and Engineering; The American University in Cairo; New Cairo; Egypt; Faculty of Biotechnology; October University for Modern Sciences and Arts; 6th October City; Cairo; Egypt
The lower convective layer (LCL) of the Atlantis II brine pool of the Red Sea is a unique environment in terms of high salinity, temperature, and high concentrations of heavy metals. Mercuric reductase enzymes functional in such extreme conditions could be considered a potential tool in the environmental detoxification of mercurial poisoning and might alleviate ecological hazards in the mining industry. Here, we constructed a mercuric reductase library from Atlantis II, from which we identified genes encoding two thermostable mercuric reductase (MerA) isoforms: one is halophilic (designated ATII-LCL) while the other is not (designated ATII-LCLNH). The ATII-LCL MerA has a short motif composed of four aspartic acids (4D414- 417) and two characteristic signature boxes that played a crucial role in its thermal stability. To further understand the mechanism behind the thermostability of the two studied enzymes, we mutated the isoform ATII-LCL-NH and found that the substitution of 2 aspartic acids (2D) at positions 415 and 416 enhanced the thermal stability, while other mutations had the opposite effect. The 2D mutant showed superior thermal tolerance, as it retained 81% of its activity after 10 min of incubation at 70�C. A three-dimensional structure prediction revealed newly formed salt bridges and H bonds in the 2D mutant compared to the parent molecule. To the best of our knowledge, this study is the first to rationally design a mercuric reductase with enhanced thermal stability, which we propose to have a strong potential in the bioremediation of mercurial poisoning. � 2019 American Society for Microbiology.