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Amini Z, Salehi H, Chehrazi M, Etemadi M, Xiang M. miRNAs and Their Target Genes Play a Critical Role in Response to Heat Stress in Cynodon dactylon (L.) Pers. Mol Biotechnol 2023; 65:2004-2017. [PMID: 36913082 DOI: 10.1007/s12033-023-00713-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Accepted: 02/27/2023] [Indexed: 03/14/2023]
Abstract
Annual global temperature is increasing rapidly. Therefore, in the near future, plants will be exposed to severe heat stress. However, the potential of microRNAs-mediated molecular mechanism for modulating the expression of their target genes is unclear. To investigate the changes of miRNAs in thermo-tolerant plants, in this study, we first investigated the impact of four high temperature regimes including 35/30 °C, 40/35 °C, 45/40 °C, and 50/45 °C in a day/night cycle for 21 days on the physiological traits (total chlorophyll, relative water content and electrolyte leakage and total soluble protein), antioxidant enzymes activities (superoxide dismutase, ascorbic peroxidase, catalase and peroxidase), and osmolytes (total soluble carbohydrates and starch) in two bermudagrass accessions named Malayer and Gorgan. The results showed that more chlorophyll and the relative water content, lower ion leakage, more efficient protein and carbon metabolism and activation of defense proteins (such as antioxidant enzymes) in Gorgan accession, led to better maintained plant growth and activity during heat stress. In the next stage, to investigate the role of miRNAs and their target genes in response to heat stress in a thermo-tolerant plant, the impact of severe heat stress (45/40 °C) was evaluated on the expression of three miRNAs (miRNA159a, miRNA160a and miRNA164f) and their target genes (GAMYB, ARF17 and NAC1, respectively). All measurements were performed in leaves and roots simultaneously. Heat stress significantly induced the expression of three miRNAs in leaves of two accession, while having different effects on the expression of these miRNAs in roots. The results showed that a decrease in the expression of the transcription factor ARF17, no change in the expression of the transcription factor NAC1, and an increase in the expression of the transcription factor GAMYB in leaf and root tissues of Gorgan accession led to improved heat tolerance in it. These results also showed that the effect of miRNAs on the modulating expression of target mRNAs in leaves and roots is different under heat stress, and miRNAs and mRNAs show spatiotemporal expression. Therefore, the simultaneous analysis of miRNAs and mRNAs expressions in shoot and roots is needed to comprehensively understand miRNAs regulatory function under heat stress.
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Affiliation(s)
- Zohreh Amini
- Department of Horticultural Science, School of Agriculture, Shiraz University, Shiraz, Iran
| | - Hassan Salehi
- Department of Horticultural Science, School of Agriculture, Shiraz University, Shiraz, Iran.
| | - Mehrangiz Chehrazi
- Department of Horticultural Science, School of Agriculture, Shahid Chamran University, Ahvaz, Iran
| | - Mohammad Etemadi
- Department of Horticultural Science, School of Agriculture, Shiraz University, Shiraz, Iran
| | - Mingying Xiang
- Department of Horticulture and Landscape Architecture, Oklahoma State University, Stillwater, OK, 74078, USA
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The atypical thioredoxin 'Alr2205', a newly identified partner of the typical 2-Cys-Peroxiredoxin, safeguards the cyanobacterium Anabaena from oxidative stress. Biochem J 2023; 480:87-104. [PMID: 36594794 DOI: 10.1042/bcj20220524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2022] [Revised: 12/20/2022] [Accepted: 01/03/2023] [Indexed: 01/04/2023]
Abstract
Thioredoxins (Trxs) are ubiquitous proteins that play vital roles in several physiological processes. Alr2205, a thioredoxin-like protein from Anabaena PCC 7120, was found to be evolutionarily closer to the Trx-domain of the NADPH-Thioredoxin Reductase C than the other thioredoxins. The Alr2205 protein showed disulfide reductase activity despite the presence a non-canonical active site motif 'CPSC'. Alr2205 not only physically interacted with, but also acted as a physiological reductant of Alr4641 (the typical 2-Cys-Peroxiredoxin from Anabaena), supporting its peroxidase function. Structurally, Alr2205 was a monomeric protein that formed an intramolecular disulfide bond between the two active site cysteines (Cys-38 and Cys-41). However, the Alr2205C41S protein, wherein the resolving cysteine was mutated to serine, was capable of forming intermolecular disulfide bond and exist as a dimer when treated with H2O2. Overproduction of Alr2205 in E. coli protected cells from heavy metals, but not oxidative stress. To delve into its physiological role, Alr2205/Alr2205C41S was overexpressed in Anabaena, and the ability of the corresponding strains (An2205+ or An2205C41S+) to withstand environmental stresses was assessed. An2205+ showed higher resistance to H2O2 than An2205C41S+, indicating that the disulfide reductase function of this protein was critical to protect cells from this peroxide. Although, An2205+ did not show increased capability to withstand cadmium stress, An2205C41S+ was more susceptible to this heavy metal. This is the first study that provides a vital understanding into the function of atypical thioredoxins in countering the toxic effects of heavy metals/H2O2 in prokaryotes.
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Chakravarty D, Bihani SC, Banerjee M, Kalwani P, Ballal A. Unique functional insights into the antioxidant response of the cyanobacterial Mn-catalase (KatB). Free Radic Biol Med 2022; 179:266-276. [PMID: 34793931 DOI: 10.1016/j.freeradbiomed.2021.11.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Accepted: 11/12/2021] [Indexed: 01/06/2023]
Abstract
KatB, a hexameric Mn-catalase, plays a vital role in overcoming oxidative and salinity stress in the ecologically important, N2-fixing cyanobacterium, Anabaena. The 5 N-terminal residues of KatB, which show a high degree of conservation in cyanobacteria, form an antiparallel β-strand at the subunit interface of the KatB hexamer. In this study, the contribution of these N-terminal non-active site residues, towards the maintenance of the structure, biochemical properties, and redox balance was evaluated. Each N-terminal amino acid residue from the 2nd to the 7th position of KatB was individually mutated to Ala (to express KatBF2A/KatBF3A/KatBH4A/KatBK5E/KatBK6A/KatBE7A) or this entire 6 amino acid stretch was deleted (to yield KatBTrunc). All the above-mentioned KatB variants, along with the wild-type KatB protein (KatBWT), were overproduced in E. coli and purified. In comparison to KatBWT, the KatBF2A/KatBH4A/KatBTrunc proteins were less compact, more prone to chemical/thermal denaturation, and were unexpectedly inactive. KatBF3A/KatBK5E/KatBK6A showed biophysical/biochemical properties that were in between that of KatBWT and KatBF2A/KatBH4A/KatBTrunc. Surprisingly, KatBE7A was more thermostable with higher activity than KatBWT. On exposure to H2O2, E. coli expressing KatBWT/KatBE7A showed considerably reduced formation of ROS and increased survival than the other KatB variants. Utilizing the KatB structure, the molecular basis responsible for the altered stability/activity of the KatB mutants was delineated. This study demonstrates the physiological importance of the N-terminal β-strand of Mn-catalases in combating H2O2 stress and shows that the non-active site residues can be used for rational protein engineering to develop Mn-catalases with improved characteristics.
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Affiliation(s)
- Dhiman Chakravarty
- Molecular Biology Division, Bhabha Atomic Research Centre, Trombay, Mumbai, 400085, India; Homi Bhabha National Institute, Anushaktinagar, Mumbai, 400094, India
| | - Subhash C Bihani
- Radiation Biology & Health Sciences Division, Trombay, Mumbai, 400085, India; Homi Bhabha National Institute, Anushaktinagar, Mumbai, 400094, India.
| | - Manisha Banerjee
- Molecular Biology Division, Bhabha Atomic Research Centre, Trombay, Mumbai, 400085, India; Homi Bhabha National Institute, Anushaktinagar, Mumbai, 400094, India
| | - Prakash Kalwani
- Molecular Biology Division, Bhabha Atomic Research Centre, Trombay, Mumbai, 400085, India; Homi Bhabha National Institute, Anushaktinagar, Mumbai, 400094, India
| | - Anand Ballal
- Molecular Biology Division, Bhabha Atomic Research Centre, Trombay, Mumbai, 400085, India; Homi Bhabha National Institute, Anushaktinagar, Mumbai, 400094, India.
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Chen K, Su C, Tang W, Zhou Y, Xu Z, Chen J, Li H, Chen M, Ma Y. Nuclear transport factor GmNTF2B-1 enhances soybean drought tolerance by interacting with oxidoreductase GmOXR17 to reduce reactive oxygen species content. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2021; 107:740-759. [PMID: 33978999 DOI: 10.1111/tpj.15319] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 04/18/2021] [Accepted: 05/03/2021] [Indexed: 05/27/2023]
Abstract
Drought is a critical abiotic stressor that modulates soybean yield. Drought stress drastically enhances reactive oxygen species (ROS) formation, and maintaining ROS content above a cytostatic level but below a cytotoxic level is essential for normal biology processes in plants. At present, most of the known ROS-scavenging systems are in the cytoplasm, and the mechanism of ROS regulation in the nucleus remains unclear. GmNTF2B-1 is a member of the IV subgroup in the nucleus transporter family. Its expression is localized to the roots and is stimulated by drought stress. In this study, the overexpression of GmNTF2B-1 was found to improve the drought tolerance of transgenic soybean by influencing the ROS content in plants. An oxidoreductase, GmOXR17, was identified to interact with GmNTF2B-1 in the nucleus through the yeast two-hybrid, coimmunoprecipitation and bimolecular fluorescence complementation assays. The drought tolerance of GmOXR17 transgenic soybean was similar to that of GmNTF2B-1. GmNTF2B-1 was expressed in both cytoplasm and nucleus, and GmOXR17 transferred from the cytoplasm to the nucleus under drought stress. The overexpression of GmNTF2B-1 enhanced the nuclear entry of GmOXR17, and the overexpression of GmNTF2B-1 or GmOXR17 could decrease the H2 O2 content and oxidation level in the nucleus. In conclusion, the interaction between GmNTF2B-1 and GmOXR17 may enhance the nuclear entry of GmOXR17, thereby enhancing nuclear ROS scavenging to improve the drought resistance of soybean.
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Affiliation(s)
- Kai Chen
- Key Laboratory of Biology and Genetic Improvement of Triticeae Crops, Institute of Crop Science, Chinese Academy of Agricultural Sciences/National Key Facility for Crop Gene Resources and Genetic Improvement, Ministry of Agriculture, Beijing, 100081, China
- College of Life Sciences, Jilin Agricultural University, Changchun, 130118, China
| | - Chen Su
- Key Laboratory of Biology and Genetic Improvement of Triticeae Crops, Institute of Crop Science, Chinese Academy of Agricultural Sciences/National Key Facility for Crop Gene Resources and Genetic Improvement, Ministry of Agriculture, Beijing, 100081, China
- Agricultural Technology Extension Center of Xi'an, Xi'an 710000, China
| | - Wensi Tang
- Key Laboratory of Biology and Genetic Improvement of Triticeae Crops, Institute of Crop Science, Chinese Academy of Agricultural Sciences/National Key Facility for Crop Gene Resources and Genetic Improvement, Ministry of Agriculture, Beijing, 100081, China
| | - Yongbin Zhou
- Key Laboratory of Biology and Genetic Improvement of Triticeae Crops, Institute of Crop Science, Chinese Academy of Agricultural Sciences/National Key Facility for Crop Gene Resources and Genetic Improvement, Ministry of Agriculture, Beijing, 100081, China
| | - Zhaoshi Xu
- Key Laboratory of Biology and Genetic Improvement of Triticeae Crops, Institute of Crop Science, Chinese Academy of Agricultural Sciences/National Key Facility for Crop Gene Resources and Genetic Improvement, Ministry of Agriculture, Beijing, 100081, China
| | - Jun Chen
- Key Laboratory of Biology and Genetic Improvement of Triticeae Crops, Institute of Crop Science, Chinese Academy of Agricultural Sciences/National Key Facility for Crop Gene Resources and Genetic Improvement, Ministry of Agriculture, Beijing, 100081, China
| | - Haiyan Li
- College of Tropical Crops, Hainan University, Haikou, 570228, China
| | - Ming Chen
- Key Laboratory of Biology and Genetic Improvement of Triticeae Crops, Institute of Crop Science, Chinese Academy of Agricultural Sciences/National Key Facility for Crop Gene Resources and Genetic Improvement, Ministry of Agriculture, Beijing, 100081, China
| | - Youzhi Ma
- Key Laboratory of Biology and Genetic Improvement of Triticeae Crops, Institute of Crop Science, Chinese Academy of Agricultural Sciences/National Key Facility for Crop Gene Resources and Genetic Improvement, Ministry of Agriculture, Beijing, 100081, China
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Vymětal J, Jakubec D, Galgonek J, Vondrášek J. Amino Acid Interactions (INTAA) web server v2.0: a single service for computation of energetics and conservation in biomolecular 3D structures. Nucleic Acids Res 2021; 49:W15-W20. [PMID: 34019656 PMCID: PMC8262704 DOI: 10.1093/nar/gkab377] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Revised: 04/10/2021] [Accepted: 04/27/2021] [Indexed: 12/29/2022] Open
Abstract
Interactions among amino acid residues are the principal contributor to the stability of the three-dimensional structure of a protein. The Amino Acid Interactions (INTAA) web server (https://bioinfo.uochb.cas.cz/INTAA/) has established itself as a unique computational resource, which enables users to calculate the contribution of individual residues in a biomolecular structure to its total energy using a molecular mechanical scoring function. In this update, we describe major additions to the web server which help solidify its position as a robust, comprehensive resource for biomolecular structure analysis. Importantly, a new continuum solvation model was introduced, allowing more accurate representation of electrostatic interactions in aqueous media. In addition, a low-overhead pipeline for the estimation of evolutionary conservation in protein chains has been added. New visualization options were introduced as well, allowing users to easily switch between and interrelate the energetic and evolutionary views of the investigated structures.
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Affiliation(s)
- Jiří Vymětal
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Praha 6, 160 00, Czech Republic
| | - David Jakubec
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Praha 6, 160 00, Czech Republic.,Department of Software Engineering, Faculty of Mathematics and Physics, Charles University, Praha 1, 118 00, Czech Republic
| | - Jakub Galgonek
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Praha 6, 160 00, Czech Republic
| | - Jiří Vondrášek
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Praha 6, 160 00, Czech Republic
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Banerjee M, Kalwani P, Chakravarty D, Singh B, Ballal A. Functional and mechanistic insights into the differential effect of the toxicant 'Se(IV)' in the cyanobacterium Anabaena PCC 7120. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2021; 236:105839. [PMID: 34015754 DOI: 10.1016/j.aquatox.2021.105839] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 04/07/2021] [Accepted: 04/12/2021] [Indexed: 06/12/2023]
Abstract
Selenium, an essential trace element for animals, poses a threat to all forms of life above a threshold concentration. The ubiquitously present cyanobacteria, a major photosynthetic biotic component of aquatic and other ecosystems, are excellent systems to study the effects of environmental toxicants. The molecular changes that led to beneficial or detrimental effects in response to different doses of selenium oxyanion Se(IV) were analyzed in the filamentous cyanobacterium Anabaena PCC 7120. This organism showed no inhibition in growth up to 15 mg/L sodium selenite, but above this dose i.e. 20-100 mg/L of Se(IV), both growth and photosynthesis were substantially inhibited. Along with the increased accumulation of non-protein thiols, a consistent reduction in levels of ROS was observed at 10 mg/mL dose of Se(IV). High dose of Se(IV) (above 20 mg/L) enhanced endogenous reactive oxygen species (ROS)/lipid peroxidation, and decreased photosynthetic capability. Treatment with 100 mg/L Se(IV) downregulated transcription of several photosynthesis pathways-related genes such as those encoding photosystem I and II proteins, phycobilisome rod-core linker protein, phycocyanobilin, phycoerythrocyanin-associated proteins etc. Interestingly, at a dose range of 10-15 mg/L Se(IV), Anabaena showed an increase in PSII photosynthetic yield and electron transport rate (at PSII), suggesting improved photosynthesis. Se was incorporated into the Anabaena cells, and Se-enriched thylakoid membranes showed higher redox conductivity than the thylakoid membranes from untreated cells. Overall, the data supports that modulation of photosynthetic machinery is one of the crucial mechanisms responsible for the dose-dependent contrasting effect of Se(IV) observed in Anabaena.
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Affiliation(s)
- Manisha Banerjee
- Molecular Biology Division; Bhabha Atomic Research Centre, Mumbai 400085, India; Homi Bhabha National Institute, Anushaktinagar, Mumbai 400094, India.
| | - Prakash Kalwani
- Molecular Biology Division; Bhabha Atomic Research Centre, Mumbai 400085, India; Homi Bhabha National Institute, Anushaktinagar, Mumbai 400094, India
| | - Dhiman Chakravarty
- Molecular Biology Division; Bhabha Atomic Research Centre, Mumbai 400085, India; Homi Bhabha National Institute, Anushaktinagar, Mumbai 400094, India
| | - Beena Singh
- Radiation and Photo Chemistry Division; Bhabha Atomic Research Centre, Mumbai 400085, India; Homi Bhabha National Institute, Anushaktinagar, Mumbai 400094, India
| | - Anand Ballal
- Molecular Biology Division; Bhabha Atomic Research Centre, Mumbai 400085, India; Homi Bhabha National Institute, Anushaktinagar, Mumbai 400094, India.
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Interaction of artemisinin protects the activity of antioxidant enzyme catalase: A biophysical study. Int J Biol Macromol 2021; 172:418-428. [PMID: 33460658 DOI: 10.1016/j.ijbiomac.2021.01.072] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 12/22/2020] [Accepted: 01/12/2021] [Indexed: 01/09/2023]
Abstract
The major antioxidant enzyme catalase is downregulated and the enzyme activity is compromised in various disease conditions such as malarial and cancer. Hence, the restoration and protection of catalase is a promising therapeutic strategy in disease management. In the present study, for the first time we have demonstrated the protective role of well-known anti-malarial drug Artemisinin (ART) on the time and temperature-induced degradation of bovine liver catalase (BLC) activity. The findings at different time intervals and at higher temperature showed the protective role of ART on BLC activity. Molecular docking studies suggested specific binding of ART on BLC through heme group interface which was further supported by cyclic voltammetry and dynamic light scattering study. The stabilization of BLC in presence of ART was mediated through forming a BLC-ART complex with reduced and shifted electrochemical peak and increased hydrodynamic diameter. ART substantially prevents the temperature-induced reduction in α-helical content with simultaneous increment in other secondary structures like antiparallel, parallel, β-turn and random coils. Nevertheless, the protective role of ART was accepted from the enhanced thermal stability and increased Tm value of BLC in presence of ART at higher temperatures. Our results uncover the mechanism of interaction between ART with BLC and suggest the protective role of ART towards spatiotemporal alteration of BLC by preventing the structural and molecular change in BLC. Thus, the findings advocate ART as a potential therapeutic drug for diseases associated with reduced catalase activity.
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Ballal A, Chakravarty D, Bihani SC, Banerjee M. Gazing into the remarkable world of non-heme catalases through the window of the cyanobacterial Mn-catalase 'KatB'. Free Radic Biol Med 2020; 160:480-487. [PMID: 32858159 DOI: 10.1016/j.freeradbiomed.2020.08.013] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 08/09/2020] [Accepted: 08/18/2020] [Indexed: 10/23/2022]
Abstract
Catalases, enzymes that decompose H2O2, are broadly categorized as heme catalases or non-heme catalases. The non-heme catalases are also known as Mn-catalases as they have Mn atoms in their active sites. However, unlike the well characterized heme-catalases, the study of Mn-catalases has gained importance only in the last few years. The filamentous, heterocystous, N2-fixing cyanobacterium Anabaena PCC 7120, shows the presence of two Mn-catalases, KatA and KatB, but lacks heme catalases. Of the two Mn-catalases, KatB, which is induced by salt/desiccation, plays a major role in overcoming salinity/oxidative stress. In this mini review, we have summarized the recent advances made in the field of Mn-catalases, particularly KatB, and have interpreted these results in the larger context of stress physiology. These aspects bring to the fore the distinctive biochemical/structural properties of Mn-catalases and furthermore highlight the in vivo importance of these enzymes in adapting to oxidative stresses.
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Affiliation(s)
- Anand Ballal
- Molecular Biology Division, Bhabha Atomic Research Centre, Trombay, Mumbai, 400085, India; Homi Bhabha National Institute, Anushaktinagar, Mumbai, 400094, India.
| | - Dhiman Chakravarty
- Molecular Biology Division, Bhabha Atomic Research Centre, Trombay, Mumbai, 400085, India; Homi Bhabha National Institute, Anushaktinagar, Mumbai, 400094, India
| | - Subhash C Bihani
- Radiation Biology and Health Sciences Division, Bhabha Atomic Research Centre, Trombay, Mumbai, 400085, India
| | - Manisha Banerjee
- Molecular Biology Division, Bhabha Atomic Research Centre, Trombay, Mumbai, 400085, India; Homi Bhabha National Institute, Anushaktinagar, Mumbai, 400094, India
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Novel molecular aspects of the CRISPR backbone protein ‘Cas7’ from cyanobacteria. Biochem J 2020; 477:971-983. [DOI: 10.1042/bcj20200026] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 02/11/2020] [Accepted: 02/13/2020] [Indexed: 01/16/2023]
Abstract
The cyanobacterium Anabaena PCC 7120 shows the presence of Type I-D CRISPR system that can potentially confer adaptive immunity. The Cas7 protein (Alr1562), which forms the backbone of the type I-D surveillance complex, was characterized from Anabaena. Alr1562, showed the presence of the non-canonical RNA recognition motif and two intrinsically disordered regions (IDRs). When overexpressed in E. coli, the Alr1562 protein was soluble and could be purified by affinity chromatography, however, deletion of IDRs rendered Alr1562 completely insoluble. The purified Alr1562 was present in the dimeric or a RNA-associated higher oligomeric form, which appeared as spiral structures under electron microscope. With RNaseA and NaCl treatment, the higher oligomeric form converted to the lower oligomeric form, indicating that oligomerization occurred due to the association of Alr1562 with RNA. The secondary structure of both these forms was largely similar, resembling that of a partially folded protein. The dimeric Alr1562 was more prone to temperature-dependent aggregation than the higher oligomeric form. In vitro, the Alr1562 bound more specifically to a minimal CRISPR unit than to the non-specific RNA. Residues required for binding of Alr1562 to RNA, identified by protein modeling-based approaches, were mutated for functional validation. Interestingly, these mutant proteins, showing reduced ability to bind RNA were predominantly present in dimeric form. Alr1562 was detected with specific antiserum in Anabaena, suggesting that the type I-D system is expressed and may be functional in vivo. This is the first report that describes the characterization of a Cas protein from any photosynthetic organism.
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Chakravarty D, Banerjee M, Ballal A. Facile generation of a biotechnologically-relevant catalase showcases the efficacy of a blue-green algal biomass as a suitable bioresource for protein overproduction. BIORESOURCE TECHNOLOGY 2019; 293:122013. [PMID: 31494434 DOI: 10.1016/j.biortech.2019.122013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 08/11/2019] [Accepted: 08/12/2019] [Indexed: 06/10/2023]
Abstract
Here, we show the utility of a cyanobacterial biomass for overproduction and easy downstream processing of the thermostable protein KatB (a Mn-catalase). The nitrogen-fixing blue-green alga, Anabaena, was bioengineered to overexpress the KatB protein (An-KatB). Interestingly, pure An-KatB could be isolated from Anabaena by a simple physical process, obviating the need of expensive resins or chromatographic steps. An-KatB was an efficient H2O2-detoxifying protein that retained all the properties of Mn-catalases. Surprisingly, the purified An-KatB showed improved characteristics than the corresponding KatB (Ec-KatB) protein purified after over-expression in E. coli. An-KatB was unaffected by exposure to high temperature (85 °C), whereas a commercially procured heme-catalase showed an appreciable drop in activity beyond 50 °C. These data convincingly demonstrate the utility of Anabaena as a competent microbial bioresource for overproduction of proteins and further highlight the advantage of An-KatB over heme-catalases in bioprocesses where H2O2 is to be decomposed at elevated temperatures.
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Affiliation(s)
- Dhiman Chakravarty
- Molecular Biology Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India; Homi Bhabha National Institute, Anushaktinagar, Mumbai 400094, India
| | - Manisha Banerjee
- Molecular Biology Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India; Homi Bhabha National Institute, Anushaktinagar, Mumbai 400094, India
| | - Anand Ballal
- Molecular Biology Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India; Homi Bhabha National Institute, Anushaktinagar, Mumbai 400094, India.
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