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Lunavat SK, Singh SS, Mohammed AQ, Nakka VP, Phanithi PB, Medisetty R, Gogada R. The MreA Metal-Binding Sites C40, H65, and C69 Play a Critical Role in the Metal Tolerance of Pseudomonas putida KT2440. Curr Microbiol 2022; 79:142. [PMID: 35322302 DOI: 10.1007/s00284-022-02804-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Metal-binding proteins occur in the cytosol of most eubacteria. The hypothetical metal responsive protein MreA (PP-2969 gene; NreA) seems responsible for zinc, chromium, cadmium accumulation, and metal ion homeostasis. However, there is a lack of definitive evidence regarding the specific metal-binding sites of MreA protein. The present study aimed to identify putative metal-binding regions for MreA. In silico analysis revealed that amino acids C40, H65, and C69 (CHC region) seem critical for metal-protein interactions. We created site-directed mutants (SDM's) of MreA for interacted amino acids to validate in silico results. The differential scanning fluorimetry (DSF) and atomic absorption spectroscopy (AAS) showed that SDM strains of MreA protein curtailed metal accumulation compared to the wild types indicating C40, H65, and C69 amino acids are critical for metal binding. Thus, we report potential implications for MreA-bioengineered strains of Pseudomonas putida KT2440 for metal ion homeostasis by alleviating metal toxicity in the biological environment.
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Affiliation(s)
- Shanti Kumari Lunavat
- Department of Biochemistry, Osmania University, Hyderabad, Telangana, 500 007, India
| | | | - Abdul Qadeer Mohammed
- Department of Biochemistry, Osmania University, Hyderabad, Telangana, 500 007, India
| | - Venkata Prasuja Nakka
- Department of Biochemistry, Acharya Nagarjuna University, Guntur, Andhra Pradesh, 522510, India
| | - Prakash-Babu Phanithi
- Department of Biotechnology and Bioinformatics, University of Hyderabad, Hyderabad, Telangana, 500046, India
| | - Rajesh Medisetty
- Department of Biochemistry, Osmania University, Hyderabad, Telangana, 500 007, India
| | - Raghu Gogada
- Department of Biotechnology and Bioinformatics, University of Hyderabad, Hyderabad, Telangana, 500046, India.
- Department of Biochemistry, Osmania University, Hyderabad, Telangana, 500 007, India.
- Department of Biochemistry and Plant Physiology, MS Swaminathan School of Agriculture, Centurion University of Technology and Management, Paralakhemundi, Odisha, 761211, India.
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Kontár S, Varečka L, Híreš M, Kryštofová S, Šimkovič M. Light-induced conidiation of Trichoderma spp. strains is accompanied by development-dependent changes in the Ca 2+ binding to cell walls. Can J Microbiol 2018; 64:856-864. [PMID: 29906398 DOI: 10.1139/cjm-2017-0747] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The effect of light on the binding of Ca2+ to mycelia and to cell walls isolated from aerial mycelia of three strains of Trichoderma spp. was studied. Two independent methods were used to measure the total Ca2+ content in mycelia and the Ca2+ bound to cell walls isolated from aerial mycelia. The results of these methods showed that the light-induced formation and maturation of conidia in Trichoderma spp. is accompanied by increased Ca2+ deposition in mycelia and cell walls. Moreover, the cultivation of Trichoderma atroviride F-534 in the presence of 45Ca2+ under circadian illumination showed that radioactivity was exclusively localized in the light-induced conidial rings of aerial mycelia. The fluorescence microscopy of chlortetracycline-stained mycelia showed that the major fraction of Ca2+ was accumulated in conidia and fructification structures, or some intracellular compartments in T. atroviride F-534 grown under circadian illumination, while only a limited amount of Ca2+ was associated with hyphal surfaces. In addition, the study of 45Ca2+ binding to cell walls revealed that T. atroviride F-534 displays both increased 45Ca2+ binding capacity and elevated affinity to 45Ca2+ binding upon illumination. The results indicate that conidia formation and (or) maturation is associated with changes in Ca2+ homeostasis.
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Affiliation(s)
- Szilvia Kontár
- a Institute of Biochemistry and Microbiology, Faculty of Chemical and Food Technology, Slovak University of Technology, Bratislava, Slovak Republic.,b Institute of Molecular Physiology and Genetics, Slovak Academy of Sciences, Bratislava, Slovak Republic
| | - L'udovít Varečka
- a Institute of Biochemistry and Microbiology, Faculty of Chemical and Food Technology, Slovak University of Technology, Bratislava, Slovak Republic
| | - Michal Híreš
- a Institute of Biochemistry and Microbiology, Faculty of Chemical and Food Technology, Slovak University of Technology, Bratislava, Slovak Republic
| | - Svetlana Kryštofová
- a Institute of Biochemistry and Microbiology, Faculty of Chemical and Food Technology, Slovak University of Technology, Bratislava, Slovak Republic
| | - Martin Šimkovič
- a Institute of Biochemistry and Microbiology, Faculty of Chemical and Food Technology, Slovak University of Technology, Bratislava, Slovak Republic
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