1
|
Majhi B, Semwal P, Mishra SK, Misra S, Chauhan PS. Arsenic stress management through arsenite and arsenate-tolerant growth-promoting bacteria in rice. Int Microbiol 2023:10.1007/s10123-023-00447-w. [PMID: 37979101 DOI: 10.1007/s10123-023-00447-w] [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: 07/18/2023] [Revised: 10/30/2023] [Accepted: 11/03/2023] [Indexed: 11/19/2023]
Abstract
Arsenic (As) contamination is a major problem affecting soil and groundwater in India, harming agricultural crops and human health. Plant growth-promoting rhizobacteria (PGPR) have emerged as promising agents for reducing As toxicity in plants. This study aimed to isolate and characterize As-tolerant PGPR from rice field soils with varying As levels in five districts of West Bengal, India. A total of 663 bacterial isolates were obtained from the different soil samples, and 10 bacterial strains were selected based on their arsenite (As-III) and arsenate (As-V) tolerant ability and multiple PGP traits, including phosphate solubilization, production of siderophore, indole acetic acid, biofilm formation, alginate, and exopolysaccharide. These isolates were identified by 16S rRNA gene sequencing analysis as Staphylococcus sp. (4), Niallia sp. (2), Priestia sp. (1), Bacillus sp. (1), Pseudomonas sp. (1), and Citricoccus sp. (1). Among the selected bacterial strains, Priestia flexa NBRI4As1 and Pseudomonas chengduensis NBRI12As1 demonstrated significant improvement in rice growth by alleviating arsenic stress under greenhouse conditions. Both strains were also able to modulate photosynthetic pigments, soluble sugar content, proline concentration, and defense enzyme activity. Reduction in As-V accumulation inoculated with NBRI4As1 was recorded highest by 53.02% and 31.48%, while As-III by NBRI12As1 38.84% and 35.98% in the roots and shoots of rice plants, respectively. Overall, this study can lead to developing efficient As-tolerant bacterial strains-based bioinoculant application packages for arsenic stress management in rice.
Collapse
Affiliation(s)
- Basudev Majhi
- Microbial Technologies Division, Council of Scientific and Industrial Research-National Botanical Research Institute (CSIR-NBRI), Rana Pratap Marg, Lucknow, 226001, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
| | - Pradeep Semwal
- Microbial Technologies Division, Council of Scientific and Industrial Research-National Botanical Research Institute (CSIR-NBRI), Rana Pratap Marg, Lucknow, 226001, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
| | - Shashank Kumar Mishra
- Microbial Technologies Division, Council of Scientific and Industrial Research-National Botanical Research Institute (CSIR-NBRI), Rana Pratap Marg, Lucknow, 226001, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
| | - Sankalp Misra
- Faculty of Biosciences, Institute of Biosciences and Technology, Shri Ramswaroop Memorial University, Lucknow-Deva Road, Barabanki, Uttar Pradesh, 225003, India
| | - Puneet Singh Chauhan
- Microbial Technologies Division, Council of Scientific and Industrial Research-National Botanical Research Institute (CSIR-NBRI), Rana Pratap Marg, Lucknow, 226001, India.
| |
Collapse
|
2
|
Characterization of Arsenic-Resistant Klebsiella pneumoniae RnASA11 from Contaminated Soil and Water Samples and Its Bioremediation Potential. Curr Microbiol 2021; 78:3258-3267. [PMID: 34230990 DOI: 10.1007/s00284-021-02602-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Accepted: 06/30/2021] [Indexed: 10/20/2022]
Abstract
Rapid industrialization and intensive agriculture activities have led to a rise in heavy metal contamination all over the world. Chhattisgarh (India) being an industrial state, the soil and water are thickly contaminated with heavy metals, especially from arsenic (As). In the present study, we isolated 108 arsenic-resistant bacteria (both from soil and water) from different arsenic-contaminated industrial and mining sites of Chhattisgarh to explore the bacterial gene pool. Further, we screened 24 potential isolates out of 108 for their ability to tolerate a high level of arsenic. The sequencing of the 16S rRNA gene of bacterial isolates revealed that all these samples belong to different diverse genera including Bacillus, Enterobacter, Klebsiella, Pantoea, Acinetobacter, Cronobacter, Pseudomonas and Agrobacterium. The metal tolerance ability was determined by amplification of arsB (arsenite efflux gene) and arsC (arsenate reductase gene) from chromosomal DNA of isolated RnASA11, which was identified as Klebsiella pneumoniae through in silico analysis. The bacterial strains RpSWA2 and RnASA11 were found to tolerate 600 mM As (V) and 30 mM As (III) but the growth of strain RpSWA2 was slower than RnASA11. Furthermore, atomic absorption spectroscopy (AAS) of the sample obtained from bioremediation assay revealed that Klebsiella pneumoniae RnASA11 was able to reduce the arsenic concentration significantly in the presence of arsenate (44%) and arsenite (38.8%) as compared to control.
Collapse
|
3
|
Marwa N, Mishra N, Singh N, Mishra A, Saxena G, Pandey V, Singh N. Effect of rhizospheric inoculation of isolated arsenic (As) tolerant strains on growth, As-uptake and bacterial communities in association with Adiantum capillus-veneris. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2020; 196:110498. [PMID: 32247957 DOI: 10.1016/j.ecoenv.2020.110498] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Revised: 03/05/2020] [Accepted: 03/16/2020] [Indexed: 05/03/2023]
Abstract
Two arsenic (As) hyper-tolerant bacterial strains NM01 Paracoccus versutus and NM04 Aeromonas caviae were isolated from As polluted site of West Bengal, India. The strains not only possess the potential to tolerate up to 20,000 mgl-1 As(V) and 10,000 mgl-1 As(III) but also possess plant growth promoting (PGP) traits like phosphate solubilization, siderophore production, IAA production. Greenhouse pot experiments were conducted to assess the effect of rhizospheric inoculation of both the strains individually and in consortia in As accumulation by Adiantum capillus-veneries. It was observed that the microbial inoculation significantly (p < 0.05) increased the synthesis of thiolic compounds and thus, enhanced As accumulation with translocation factor (TF) > 1. The strains regulated endogenous phytohormone up to 90% and 77.9% increase in auxin of consortia inoculated root and shoot, respectively. Interestingly, inoculation of the isolated strains augmented rhizospheric microbial diversity which was negatively affected by heavy metal. The results of high-throughput Illumina MiSeq sequencing technique to observe the composition of the bacterial community revealed 11,536 unique bacterial operational taxonomic units (OTUs) from As + S (non-inoculated), whereas 11,884 from Consortia As + S (inoculated) rhizospheric soil samples. Inoculated soil displayed higher bacterial diversity indices (ACE and Chao 1) with the dominant bacterial phyla Proteobacteria, Actinobacteria and Firmicutes. Our results highlight the innate PGP abilities of the strains and its potential to facilitate phytoextraction by enhancing As accumulation in the shoot.
Collapse
Affiliation(s)
- Naina Marwa
- Plant Ecology and Climate Change Science, National Botanical Research Institute, Rana Pratap Marg, Lucknow, 226001, UP, India; Department of Botany, University of Lucknow, UP, India.
| | - Nishtha Mishra
- Division of Microbial Technology, National Botanical Research Institute, Rana Pratap Marg, Lucknow, 226001, UP, India
| | - Namrata Singh
- Plant Ecology and Climate Change Science, National Botanical Research Institute, Rana Pratap Marg, Lucknow, 226001, UP, India
| | - Aradhana Mishra
- Division of Microbial Technology, National Botanical Research Institute, Rana Pratap Marg, Lucknow, 226001, UP, India
| | - Gauri Saxena
- Department of Botany, University of Lucknow, UP, India
| | - Vivek Pandey
- Plant Ecology and Climate Change Science, National Botanical Research Institute, Rana Pratap Marg, Lucknow, 226001, UP, India
| | - Nandita Singh
- Plant Ecology and Climate Change Science, National Botanical Research Institute, Rana Pratap Marg, Lucknow, 226001, UP, India.
| |
Collapse
|
4
|
Marwa N, Singh N, Srivastava S, Saxena G, Pandey V, Singh N. Characterizing the hypertolerance potential of two indigenous bacterial strains (Bacillus flexus and Acinetobacter junii) and their efficacy in arsenic bioremediation. J Appl Microbiol 2019; 126:1117-1127. [PMID: 30556924 DOI: 10.1111/jam.14179] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Revised: 11/30/2018] [Accepted: 12/11/2018] [Indexed: 11/27/2022]
Abstract
AIMS The aims of the study were to (i) isolate and characterize arsenic-tolerant bacterial strains, (ii) study the plant growth-promoting traits and (iii) explore their bioremediation potential. METHODS AND RESULTS Indigenous arsenic hypertolerant bacterial isolates NM02 and NM03 were screened as they were capable of growing at 150 mmol l-1 As (V) and 70 mmol l-1 As (III). They were identified on the basis of morphological, physiological and biochemical parameter and 16sDNA sequence as Bacillus flexus and Acinetobacter junii respectively. Genomic DNA analysis for the investigation of ars operon revealed the presence of metalloregulatory arsC gene, suggesting their ability to detoxify arsenic. The analysis for siderophore, phosphate solubilization, indole acetic acid (IAA) and ACC deaminase highlighted the intrinsic plant growth-promoting rhizobacteria traits of both the bacterial strains. The energy dispersive spectroscopy analysis proved the potential of cellular arsenic sequestration within the strains. Moreover, Fourier-transform infrared spectra revealed the repositioning of the spectral bands in As presence, indicating the presence of those functional groups on the bacterial surface that is involved in As adsorption. CONCLUSIONS Our results indicate that bacterial strains NM02 and NM03 were identified as potent applicants for arsenic bioremediation and possess the ability to facilitate plant growth. SIGNIFICANCE AND IMPACT OF THE STUDY The bacterial strains are proficient in As detoxification and can be employed for arsenic bioremediation; a cost-effective and in situ remediation technique for the polluted soil.
Collapse
Affiliation(s)
- N Marwa
- Plant Ecology and Environmental Sciences, CSIR-National Botanical Research Institute, Lucknow, Uttar Pradesh, India.,Department of Botany, University of Lucknow, Lucknow, Uttar Pradesh, India
| | - N Singh
- Plant Ecology and Environmental Sciences, CSIR-National Botanical Research Institute, Lucknow, Uttar Pradesh, India
| | - S Srivastava
- Department of Plant-Microbe Interaction, CSIR- National Botanical Research Institute, Lucknow, Uttar Pradesh, India
| | - G Saxena
- Department of Botany, University of Lucknow, Lucknow, Uttar Pradesh, India
| | - V Pandey
- Plant Ecology and Environmental Sciences, CSIR-National Botanical Research Institute, Lucknow, Uttar Pradesh, India
| | - N Singh
- Plant Ecology and Environmental Sciences, CSIR-National Botanical Research Institute, Lucknow, Uttar Pradesh, India
| |
Collapse
|
5
|
Satyapal GK, Mishra SK, Srivastava A, Ranjan RK, Prakash K, Haque R, Kumar N. Possible bioremediation of arsenic toxicity by isolating indigenous bacteria from the middle Gangetic plain of Bihar, India. ACTA ACUST UNITED AC 2018. [PMID: 29541605 PMCID: PMC5849785 DOI: 10.1016/j.btre.2018.02.002] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
In middle Gangetic plains, high arsenic concentration is present in water, which causes a significant health risk. Two bacterial isolates, AK1 (KY569423) and AK9 (KY569424) were isolated and characterised for Arsenic detoxification. aoxR, aoxB and aoxC genes were also observed in the isolated starin which help in arsenic detoxification by oxidation method.
In middle Gangetic plain, high arsenic concentration is present in water, which causes a significant health risk. Total 48 morphologically distinct arsenite resistant bacteria were isolated from middle Gangetic plain. The minimum inhibitory concentration (MIC) values of arsenite varied widely in the range 1–15 mM of the isolates. On the basis of their MIC, two isolates, AK1 (KY569423) and AK9 (KY569424) were selected. The analysis of the 16S rRNA gene sequence of selected isolates revealed that they are belong to the genus Pseudomonas. The AgNO3 test based microplate method revealed that isolates, AK1 and AK9, have potential in transformation of arsenic species. Further, the presence of aoxR, aoxB and aoxC genes in the both isolated strain AK1 and AK9 was confirmed, which play an important role in arsenic bioremediation by arsenite oxidation. Isolated strains also showed heavy metal resistance against Cr(IV), Ni(II), Co(II), Pb(II), Cu(II), Hg(II), Ag(I) and Cd(II).
Collapse
Affiliation(s)
- Ghanshyam Kumar Satyapal
- Centre for Biological Sciences (Biotechnology), Central University of South Bihar, Patna, Bihar, India
| | - Santosh Kumar Mishra
- Centre for Biological Sciences (Biotechnology), Central University of South Bihar, Patna, Bihar, India
| | - Amrita Srivastava
- Centre for Biological Sciences (Life Science), Central University of South Bihar, Patna, Bihar, India
| | - Rajesh Kumar Ranjan
- Centre for Environmental Sciences, Central University of South Bihar, Patna, Bihar, India
| | - Krishna Prakash
- Centre for Biological Sciences (Biotechnology), Central University of South Bihar, Patna, Bihar, India
| | - Rizwanul Haque
- Centre for Biological Sciences (Biotechnology), Central University of South Bihar, Patna, Bihar, India
| | - Nitish Kumar
- Centre for Biological Sciences (Biotechnology), Central University of South Bihar, Patna, Bihar, India
| |
Collapse
|
6
|
Nguyen VK, Tran HT, Park Y, Yu J, Lee T. Microbial arsenite oxidation with oxygen, nitrate, or an electrode as the sole electron acceptor. ACTA ACUST UNITED AC 2017; 44:857-868. [DOI: 10.1007/s10295-017-1910-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Accepted: 01/29/2017] [Indexed: 10/20/2022]
Abstract
Abstract
The purpose of this study was to identify bacteria that can perform As(III) oxidation for environmental bioremediation. Two bacterial strains, named JHS3 and JHW3, which can autotrophically oxidize As(III)–As(V) with oxygen as an electron acceptor, were isolated from soil and water samples collected in the vicinity of an arsenic-contaminated site. According to 16S ribosomal RNA sequence analysis, both strains belong to the ɤ-Proteobacteria class and share 99% sequence identity with previously described strains. JHS3 appears to be a new strain of the Acinetobacter genus, whereas JHW3 is likely to be a novel strain of the Klebsiella genus. Both strains possess the aioA gene encoding an arsenite oxidase and are capable of chemolithoautotrophic growth in the presence of As(III) up to 10 mM as a primary electron donor. Cell growth and As(III) oxidation rate of both strains were significantly enhanced during cultivation under heterotrophic conditions. Under anaerobic conditions, only strain JHW3 oxidized As(III) using nitrate or a solid-state electrode of a bioelectrochemical system as a terminal electron acceptor. Kinetic studies of As(III) oxidation under aerobic condition demonstrated a higher V max and K m from strain JHW3 than strain JHS3. This study indicated the potential application of strain JHW3 for remediation of subsurface environments contaminated with arsenic.
Collapse
Affiliation(s)
- Van Khanh Nguyen
- 0000 0001 2218 7142 grid.255166.3 Department of Environmental Engineering Dong-a University 49315 Busan Republic of Korea
| | - Huong T Tran
- 0000 0001 0719 8572 grid.262229.f Department of Molecular Biology Pusan National University 46241 Busan Republic of Korea
| | - Younghyun Park
- 0000 0001 0719 8572 grid.262229.f Department of Civil and Environmental Engineering Pusan National University No. 2 Busandaehak-ro 63beon-gil, Geumjeong-gu 46241 Busan Republic of Korea
| | - Jaecheul Yu
- 0000 0001 0719 8572 grid.262229.f Department of Civil and Environmental Engineering Pusan National University No. 2 Busandaehak-ro 63beon-gil, Geumjeong-gu 46241 Busan Republic of Korea
| | - Taeho Lee
- 0000 0001 0719 8572 grid.262229.f Department of Civil and Environmental Engineering Pusan National University No. 2 Busandaehak-ro 63beon-gil, Geumjeong-gu 46241 Busan Republic of Korea
| |
Collapse
|
7
|
Zhang Z, Yin N, Cai X, Wang Z, Cui Y. Arsenic redox transformation by Pseudomonas sp. HN-2 isolated from arsenic-contaminated soil in Hunan, China. J Environ Sci (China) 2016; 47:165-173. [PMID: 27593283 DOI: 10.1016/j.jes.2015.11.036] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Revised: 10/12/2015] [Accepted: 11/04/2015] [Indexed: 06/06/2023]
Abstract
A mesophilic, Gram-negative, arsenite[As(III)]-oxidizing and arsenate[As(V)]-reducing bacterial strain, Pseudomonas sp. HN-2, was isolated from an As-contaminated soil. Phylogenetic analysis based on 16S rRNA gene sequencing indicated that the strain was closely related to Pseudomonas stutzeri. Under aerobic conditions, this strain oxidized 92.0% (61.4μmol/L) of arsenite to arsenate within 3hr of incubation. Reduction of As(V) to As(III) occurred in anoxic conditions. Pseudomonas sp. HN-2 is among the first soil bacteria shown to be capable of both aerobic As(III) oxidation and anoxic As(V) reduction. The strain, as an efficient As(III) oxidizer and As(V) reducer in Pseudomonas, has the potential to impact arsenic mobility in both anoxic and aerobic environments, and has potential application in As remediation processes.
Collapse
Affiliation(s)
- Zhennan Zhang
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 101408, China; Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
| | - Naiyi Yin
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 101408, China; Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Xiaolin Cai
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 101408, China; Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Zhenzhou Wang
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 101408, China; Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Yanshan Cui
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 101408, China; Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
| |
Collapse
|
8
|
Arsenite oxidizing multiple metal resistant bacteria isolated from industrial effluent: their potential use in wastewater treatment. World J Microbiol Biotechnol 2016; 32:133. [DOI: 10.1007/s11274-016-2079-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Accepted: 04/29/2016] [Indexed: 10/21/2022]
|
9
|
Singh N, Marwa N, Mishra SK, Mishra J, Verma PC, Rathaur S, Singh N. Brevundimonas diminuta mediated alleviation of arsenic toxicity and plant growth promotion in Oryza sativa L. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2016; 125:25-34. [PMID: 26650422 DOI: 10.1016/j.ecoenv.2015.11.020] [Citation(s) in RCA: 81] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Revised: 10/13/2015] [Accepted: 11/18/2015] [Indexed: 05/27/2023]
Abstract
Arsenic (As), a toxic metalloid adversely affects plant growth in polluted areas. In the present study, we investigated the possibility of improving phytostablization of arsenic through application of new isolated strain Brevundimonas diminuta (NBRI012) in rice plant [Oryza sativa (L.) Var. Sarju 52] at two different concentrations [10ppm (low toxic) and 50ppm (high toxic)] of As. The plant growth promoting traits of bacterial strains revealed the inherent ability of siderophores, phosphate solubilisation, indole acetic acid (IAA), 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase production which may be associated with increased biomass, chlorophyll and MDA content of rice and thereby promoting plant growth. The study also revealed the As accumulation property of NBRI012 strain which could play an important role in As removal from contaminated soil. Furthermore, NBRI012 inoculation significantly restored the hampered root epidermal and cortical cell growth of rice plant and root hair elimination. Altogether our study highlights the multifarious role of B. diminuta in mediating stress tolerance and modulating translocation of As in edible part of rice plant.
Collapse
Affiliation(s)
- Namrata Singh
- Eco-auditing group, CSIR-National Botanical Research Institute, Lucknow, India.
| | - Naina Marwa
- Eco-auditing group, CSIR-National Botanical Research Institute, Lucknow, India
| | - Shashank K Mishra
- Plant Microbe Interaction Division, National Botanical Research Institute, Rana Pratap Marg, Lucknow 226001, UP, India
| | - Jyoti Mishra
- Plant Molecular Biology and Genetic Engineering Division, National Botanical Research Institute, Rana Pratap Marg, Lucknow 226001, UP, India
| | - Praveen C Verma
- Plant Molecular Biology and Genetic Engineering Division, National Botanical Research Institute, Rana Pratap Marg, Lucknow 226001, UP, India
| | - Sushma Rathaur
- Department of Biochemistry, Banaras Hindu University, Varanasi, India
| | - Nandita Singh
- Eco-auditing group, CSIR-National Botanical Research Institute, Lucknow, India.
| |
Collapse
|
10
|
Biotechnological applications derived from microorganisms of the Atacama Desert. BIOMED RESEARCH INTERNATIONAL 2014; 2014:909312. [PMID: 25147824 PMCID: PMC4132489 DOI: 10.1155/2014/909312] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Revised: 06/29/2014] [Accepted: 07/07/2014] [Indexed: 01/18/2023]
Abstract
The Atacama Desert in Chile is well known for being the driest and oldest desert on Earth. For these same reasons, it is also considered a good analog model of the planet Mars. Only a few decades ago, it was thought that this was a sterile place, but in the past years fascinating adaptations have been reported in the members of the three domains of life: low water availability, high UV radiation, high salinity, and other environmental stresses. However, the biotechnological applications derived from the basic understanding and characterization of these species, with the notable exception of copper bioleaching, are still in its infancy, thus offering an immense potential for future development.
Collapse
|
11
|
Brautigam CA, Ouyang Z, Deka RK, Norgard MV. Sequence, biophysical, and structural analyses of the PstS lipoprotein (BB0215) from Borrelia burgdorferi reveal a likely binding component of an ABC-type phosphate transporter. Protein Sci 2013; 23:200-12. [PMID: 24318969 DOI: 10.1002/pro.2406] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2013] [Revised: 12/03/2013] [Accepted: 12/04/2013] [Indexed: 01/23/2023]
Abstract
The Lyme disease agent Borrelia burgdorferi, which is transmitted via a tick vector, is dependent on its tick and mammalian hosts for a number of essential nutrients. Like other bacterial diderms, it must transport these biochemicals from the extracellular milieu across two membranes, ultimately to the B. burgdorferi cytoplasm. In the current study, we established that a gene cluster comprising genes bb0215 through bb0218 is cotranscribed and is therefore an operon. Sequence analysis of these proteins suggested that they are the components of an ABC-type transporter responsible for translocating phosphate anions from the B. burgdorferi periplasm to the cytoplasm. Biophysical experiments established that the putative ligand-binding protein of this system, BbPstS (BB0215), binds to phosphate in solution. We determined the high-resolution (1.3 Å) crystal structure of the protein in the absence of phosphate, revealing that the protein's fold is similar to other phosphate-binding proteins, and residues that are implicated in phosphate binding in other such proteins are conserved in BbPstS. Taken together, the gene products of bb0215-0218 function as a phosphate transporter for B. burgdorferi.
Collapse
Affiliation(s)
- Chad A Brautigam
- Department of Biophysics, The University of Texas Southwestern Medical Center, Dallas, Texas, 75390
| | | | | | | |
Collapse
|
12
|
The molecular basis of phosphate discrimination in arsenate-rich environments. Nature 2012; 491:134-7. [PMID: 23034649 DOI: 10.1038/nature11517] [Citation(s) in RCA: 141] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2012] [Accepted: 08/15/2012] [Indexed: 11/08/2022]
Abstract
Arsenate and phosphate are abundant on Earth and have striking similarities: nearly identical pK(a) values, similarly charged oxygen atoms, and thermochemical radii that differ by only 4% (ref. 3). Phosphate is indispensable and arsenate is toxic, but this extensive similarity raises the question whether arsenate may substitute for phosphate in certain niches. However, whether it is used or excluded, discriminating phosphate from arsenate is a paramount challenge. Enzymes that utilize phosphate, for example, have the same binding mode and kinetic parameters as arsenate, and the latter's presence therefore decouples metabolism. Can proteins discriminate between these two anions, and how would they do so? In particular, cellular phosphate uptake systems face a challenge in arsenate-rich environments. Here we describe a molecular mechanism for this process. We examined the periplasmic phosphate-binding proteins (PBPs) of the ABC-type transport system that mediates phosphate uptake into bacterial cells, including two PBPs from the arsenate-rich Mono Lake Halomonas strain GFAJ-1. All PBPs tested are capable of discriminating phosphate over arsenate at least 500-fold. The exception is one of the PBPs of GFAJ-1 that shows roughly 4,500-fold discrimination and its gene is highly expressed under phosphate-limiting conditions. Sub-ångström-resolution structures of Pseudomonas fluorescens PBP with both arsenate and phosphate show a unique mode of binding that mediates discrimination. An extensive network of dipole-anion interactions, and of repulsive interactions, results in the 4% larger arsenate distorting a unique low-barrier hydrogen bond. These features enable the phosphate transport system to bind phosphate selectively over arsenate (at least 10(3) excess) even in highly arsenate-rich environments.
Collapse
|