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Aguilar-Carrillo Y, Soto-Urzúa L, Martínez-Martínez MDLÁ, Becerril-Ramírez M, Martínez-Morales LJ. Computational Analysis of the Tripartite Interaction of Phasins (PhaP4 and 5)-Sigma Factor (σ 24)-DNA of Azospirillum brasilense Sp7. Polymers (Basel) 2024; 16:611. [PMID: 38475295 DOI: 10.3390/polym16050611] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Revised: 02/04/2024] [Accepted: 02/07/2024] [Indexed: 03/14/2024] Open
Abstract
Azospirillum brasilense Sp7 produces PHB, which is covered by granule-associated proteins (GAPs). Phasins are the main GAPs. Previous studies have shown phasins can regulate PHB synthesis. When A. brasilense grows under stress conditions, it uses sigma factors to transcribe genes for survival. One of these factors is the σ24 factor. This study determined the possible interaction between phasins and the σ24 factor or phasin-σ24 factor complex and DNA. Three-dimensional structures of phasins and σ24 factor structures were predicted using the I-TASSER and SWISS-Model servers, respectively. Subsequently, a molecular docking between phasins and the σ24 factor was performed using the ClusPro 2.0 server, followed by molecular docking between protein complexes and DNA using the HDOCK server. Evaluation of the types of ligand-receptor interactions was performed using the BIOVIA Discovery Visualizer for three-dimensional diagrams, as well as the LigPlot server to obtain bi-dimensional diagrams. The results showed the phasins (Pha4Abs7 or Pha5Abs7)-σ24 factor complex was bound near the -35 box of the promoter region of the phaC gene. However, in the individual interaction of PhaP5Abs7 and the σ24 factor, with DNA, both proteins were bound to the -35 box. This did not occur with PhaP4Abs7, which was bound to the -10 box. This change could affect the transcription level of the phaC gene and possibly affect PHB synthesis.
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Affiliation(s)
- Yovani Aguilar-Carrillo
- Centro de Investigaciones en Ciencias Microbiológicas, Instituto de Ciencias, Benemérita Universidad Autónoma de Puebla, Av. San Claudio y Av. 24 Sur, Col. San Manuel Ciudad Universitaria, Puebla 72570, Mexico
| | - Lucía Soto-Urzúa
- Centro de Investigaciones en Ciencias Microbiológicas, Instituto de Ciencias, Benemérita Universidad Autónoma de Puebla, Av. San Claudio y Av. 24 Sur, Col. San Manuel Ciudad Universitaria, Puebla 72570, Mexico
| | - María De Los Ángeles Martínez-Martínez
- Centro de Investigaciones en Ciencias Microbiológicas, Instituto de Ciencias, Benemérita Universidad Autónoma de Puebla, Av. San Claudio y Av. 24 Sur, Col. San Manuel Ciudad Universitaria, Puebla 72570, Mexico
| | - Mirian Becerril-Ramírez
- Centro de Investigaciones en Ciencias Microbiológicas, Instituto de Ciencias, Benemérita Universidad Autónoma de Puebla, Av. San Claudio y Av. 24 Sur, Col. San Manuel Ciudad Universitaria, Puebla 72570, Mexico
| | - Luis Javier Martínez-Morales
- Centro de Investigaciones en Ciencias Microbiológicas, Instituto de Ciencias, Benemérita Universidad Autónoma de Puebla, Av. San Claudio y Av. 24 Sur, Col. San Manuel Ciudad Universitaria, Puebla 72570, Mexico
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Quelas JI, Cabrera JJ, Díaz-Peña R, Sánchez-Schneider L, Jiménez-Leiva A, Tortosa G, Delgado MJ, Pettinari MJ, Lodeiro AR, del Val C, Mesa S. Pleiotropic Effects of PhaR Regulator in Bradyrhizobium diazoefficiens Microaerobic Metabolism. Int J Mol Sci 2024; 25:2157. [PMID: 38396833 PMCID: PMC10888616 DOI: 10.3390/ijms25042157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2023] [Revised: 02/02/2024] [Accepted: 02/05/2024] [Indexed: 02/25/2024] Open
Abstract
Bradyrhizobium diazoefficiens can live inside soybean root nodules and in free-living conditions. In both states, when oxygen levels decrease, cells adjust their protein pools by gene transcription modulation. PhaR is a transcription factor involved in polyhydroxyalkanoate (PHA) metabolism but also plays a role in the microaerobic network of this bacterium. To deeply uncover the function of PhaR, we applied a multipronged approach, including the expression profile of a phaR mutant at the transcriptional and protein levels under microaerobic conditions, and the identification of direct targets and of proteins associated with PHA granules. Our results confirmed a pleiotropic function of PhaR, affecting several phenotypes, in addition to PHA cycle control. These include growth deficiency, regulation of carbon and nitrogen allocation, and bacterial motility. Interestingly, PhaR may also modulate the microoxic-responsive regulatory network by activating the expression of fixK2 and repressing nifA, both encoding two transcription factors relevant for microaerobic regulation. At the molecular level, two PhaR-binding motifs were predicted and direct control mediated by PhaR determined by protein-interaction assays revealed seven new direct targets for PhaR. Finally, among the proteins associated with PHA granules, we found PhaR, phasins, and other proteins, confirming a dual function of PhaR in microoxia.
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Affiliation(s)
- Juan I. Quelas
- Instituto de Biotecnología y Biología Molecular, Facultad de Ciencias Exactas, Universidad Nacional de La Plata y CCT-La Plata, CONICET, La Plata 1900, Argentina; (J.I.Q.); (A.R.L.)
- YPF Tecnología S.A. (Y-TEC), Avenida. del Petróleo Argentino s/n (1923), Berisso 1923, Argentina
| | - Juan J. Cabrera
- Department of Soil and Plant Microbiology, Estación Experimental del Zaidín, CSIC, 18008 Granada, Spain; (J.J.C.); (L.S.-S.); (A.J.-L.); (G.T.); (M.J.D.)
| | - Rocío Díaz-Peña
- IQUIBICEN-CONICET, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Intendente Güiraldes, C1428EHA, CABA, Buenos Aires 2160, Argentina; (R.D.-P.); (M.J.P.)
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Intendente Güiraldes, C1428EHA, CABA, Buenos Aires 2160, Argentina
| | - Lucía Sánchez-Schneider
- Department of Soil and Plant Microbiology, Estación Experimental del Zaidín, CSIC, 18008 Granada, Spain; (J.J.C.); (L.S.-S.); (A.J.-L.); (G.T.); (M.J.D.)
- Department of Computer Science and Artificial Intelligence, Andalusian Research Institute in Data Science and Computational Intelligence (DaSCI), University of Granada, 18016 Granada, Spain;
| | - Andrea Jiménez-Leiva
- Department of Soil and Plant Microbiology, Estación Experimental del Zaidín, CSIC, 18008 Granada, Spain; (J.J.C.); (L.S.-S.); (A.J.-L.); (G.T.); (M.J.D.)
| | - Germán Tortosa
- Department of Soil and Plant Microbiology, Estación Experimental del Zaidín, CSIC, 18008 Granada, Spain; (J.J.C.); (L.S.-S.); (A.J.-L.); (G.T.); (M.J.D.)
| | - María J. Delgado
- Department of Soil and Plant Microbiology, Estación Experimental del Zaidín, CSIC, 18008 Granada, Spain; (J.J.C.); (L.S.-S.); (A.J.-L.); (G.T.); (M.J.D.)
| | - M. Julia Pettinari
- IQUIBICEN-CONICET, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Intendente Güiraldes, C1428EHA, CABA, Buenos Aires 2160, Argentina; (R.D.-P.); (M.J.P.)
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Intendente Güiraldes, C1428EHA, CABA, Buenos Aires 2160, Argentina
| | - Aníbal R. Lodeiro
- Instituto de Biotecnología y Biología Molecular, Facultad de Ciencias Exactas, Universidad Nacional de La Plata y CCT-La Plata, CONICET, La Plata 1900, Argentina; (J.I.Q.); (A.R.L.)
- Cátedra de Genética, Facultad de Ciencias Agrarias y Forestales, Universidad Nacional de La Plata, La Plata 1900, Argentina
| | - Coral del Val
- Department of Computer Science and Artificial Intelligence, Andalusian Research Institute in Data Science and Computational Intelligence (DaSCI), University of Granada, 18016 Granada, Spain;
| | - Socorro Mesa
- Department of Soil and Plant Microbiology, Estación Experimental del Zaidín, CSIC, 18008 Granada, Spain; (J.J.C.); (L.S.-S.); (A.J.-L.); (G.T.); (M.J.D.)
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Enhancement of polyhydroxybutyrate production by introduction of heterologous phasin combination in Escherichia coli. Int J Biol Macromol 2023; 225:757-766. [PMID: 36400208 DOI: 10.1016/j.ijbiomac.2022.11.138] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Revised: 11/13/2022] [Accepted: 11/14/2022] [Indexed: 11/17/2022]
Abstract
Phasin is a surface-binding protein of polyhydroxyalkanoate (PHA) granules that is encoded by the phaP gene. As its expression increases, PHA granules become smaller, to increase their surface area, and are densely packed inside the cell, thereby increasing the PHA content. A wide range of PHA-producing bacteria have phaP genes; however, their PHA productivity differs, although they are derived from the cognate bacterial host cell. Modulating phasin expression could be a new strategy to enhance PHA production. This study aimed to characterize the effect of heterologous phasins on the reconstitution of E. coli BL21(DE3) and determine the best synergistic phaP gene combination to produce polyhydroxybutyrate (PHB). We identified novel phasins from a PHB high-producer strain, Halomonas sp. YLGW01, and introduced a combination of phaP genes into Escherichia coli. The resulting E. coli phaP1,3 strain had enhanced PHB production by 2.9-fold, leading to increased cell mass and increased PHB content from 48 % to 65 %. This strain also showed increased tolerance to inhibitors, such as furfural and vanillin, enabling the utilization of lignocellulose biosugar as a carbon source. These results suggested that the combination of phaP1 and phaP3 genes from H. sp. YLGW01 could increase PHB production and robustness.
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Borrero‐de Acuña JM, Poblete‐Castro I. Rational engineering of natural polyhydroxyalkanoates producing microorganisms for improved synthesis and recovery. Microb Biotechnol 2022; 16:262-285. [PMID: 35792877 PMCID: PMC9871526 DOI: 10.1111/1751-7915.14109] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Accepted: 06/14/2022] [Indexed: 01/27/2023] Open
Abstract
Microbial production of biopolymers derived from renewable substrates and waste streams reduces our heavy reliance on petrochemical plastics. One of the most important biodegradable polymers is the family of polyhydroxyalkanoates (PHAs), naturally occurring intracellular polyoxoesters produced for decades by bacterial fermentation of sugars and fatty acids at the industrial scale. Despite the advances, PHA production still suffers from heavy costs associated with carbon substrates and downstream processing to recover the intracellular product, thus restricting market positioning. In recent years, model-aided metabolic engineering and novel synthetic biology approaches have spurred our understanding of carbon flux partitioning through competing pathways and cellular resource allocation during PHA synthesis, enabling the rational design of superior biopolymer producers and programmable cellular lytic systems. This review describes these attempts to rationally engineering the cellular operation of several microbes to elevate PHA production on specific substrates and waste products. We also delve into genome reduction, morphology, and redox cofactor engineering to boost PHA biosynthesis. Besides, we critically evaluate engineered bacterial strains in various fermentation modes in terms of PHA productivity and the period required for product recovery.
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Affiliation(s)
| | - Ignacio Poblete‐Castro
- Biosystems Engineering LaboratoryDepartment of Chemical and Bioprocess EngineeringUniversidad de Santiago de Chile (USACH)SantiagoChile
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Lee HS, Lee HJ, Kim SH, Cho JY, Suh MJ, Ham S, Bhatia SK, Gurav R, Kim YG, Lee EY, Yang YH. Novel phasins from the Arctic Pseudomonas sp. B14-6 enhance the production of polyhydroxybutyrate and increase inhibitor tolerance. Int J Biol Macromol 2021; 190:722-729. [PMID: 34506862 DOI: 10.1016/j.ijbiomac.2021.08.236] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Revised: 08/18/2021] [Accepted: 08/31/2021] [Indexed: 01/17/2023]
Abstract
Phasin (PhaP), one of the polyhydroxyalkanoate granule-associated protein, enhances cell growth and polyhydroxybutyrate (PHB) biosynthesis by regulating the number and size of PHB granules. However, few studies have applied phasins to various PHB production conditions. In this study, we identified novel phasin genes from the genomic data of Arctic soil bacterium Pseudomonas sp. B14-6 and determined the role of phaP1Ps under different PHB production conditions. Transmission electron microscopy and gel permeation chromatography revealed small PHB granules with high-molecular weight, while differential scanning calorimetry showed that the extracted PHB films had similar thermal properties. The phasin protein derived from Pseudomonas sp. B14-6 revealed higher PHB production and exhibited higher tolerance to several lignocellulosic biosugar-based inhibitors than the phasin protein of Ralstonia eutropha H16 in a recombinant Escherichia coli strain. The increased tolerance to propionate, temperature, and other inhibitors was attributed to the introduction of phaP1Ps, which increased PHB production from lignocellulosic hydrolysate (2.39-fold) in the phaP1Ps strain. However, a combination of phasin proteins isolated from two different sources did not increase PHB production. These findings suggest that phasin could serve as a powerful means to increase robustness and PHB production in heterologous strains.
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Affiliation(s)
- Hye Soo Lee
- Department of Biological Engineering, College of Engineering, Konkuk University, Seoul 05029, Republic of Korea
| | - Hong-Ju Lee
- Department of Biological Engineering, College of Engineering, Konkuk University, Seoul 05029, Republic of Korea
| | - Sang Hyun Kim
- Department of Biological Engineering, College of Engineering, Konkuk University, Seoul 05029, Republic of Korea
| | - Jang Yeon Cho
- Department of Biological Engineering, College of Engineering, Konkuk University, Seoul 05029, Republic of Korea
| | - Min Ju Suh
- Department of Biological Engineering, College of Engineering, Konkuk University, Seoul 05029, Republic of Korea
| | - Sion Ham
- Department of Biological Engineering, College of Engineering, Konkuk University, Seoul 05029, Republic of Korea
| | - Shashi Kant Bhatia
- Department of Biological Engineering, College of Engineering, Konkuk University, Seoul 05029, Republic of Korea; Institute for Ubiquitous Information Technology and Applications, Konkuk University, Seoul 05029, Republic of Korea.
| | - Ranjit Gurav
- Department of Biological Engineering, College of Engineering, Konkuk University, Seoul 05029, Republic of Korea.
| | - Yun-Gon Kim
- Department of Chemical Engineering, Soongsil University, Seoul 06978, Republic of Korea.
| | - Eun Yeol Lee
- Department of Chemical Engineering, Kyung Hee University, Yongin-si, Gyeonggi-do 17104, Republic of Korea.
| | - Yung-Hun Yang
- Department of Biological Engineering, College of Engineering, Konkuk University, Seoul 05029, Republic of Korea; Institute for Ubiquitous Information Technology and Applications, Konkuk University, Seoul 05029, Republic of Korea.
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Turco R, Santagata G, Corrado I, Pezzella C, Di Serio M. In vivo and Post-synthesis Strategies to Enhance the Properties of PHB-Based Materials: A Review. Front Bioeng Biotechnol 2021; 8:619266. [PMID: 33585417 PMCID: PMC7874203 DOI: 10.3389/fbioe.2020.619266] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Accepted: 11/30/2020] [Indexed: 12/13/2022] Open
Abstract
The transition toward "green" alternatives to petroleum-based plastics is driven by the need for "drop-in" replacement materials able to combine characteristics of existing plastics with biodegradability and renewability features. Promising alternatives are the polyhydroxyalkanoates (PHAs), microbial biodegradable polyesters produced by a wide range of microorganisms as carbon, energy, and redox storage material, displaying properties very close to fossil-fuel-derived polyolefins. Among PHAs, polyhydroxybutyrate (PHB) is by far the most well-studied polymer. PHB is a thermoplastic polyester, with very narrow processability window, due to very low resistance to thermal degradation. Since the melting temperature of PHB is around 170-180°C, the processing temperature should be at least 180-190°C. The thermal degradation of PHB at these temperatures proceeds very quickly, causing a rapid decrease in its molecular weight. Moreover, due to its high crystallinity, PHB is stiff and brittle resulting in very poor mechanical properties with low extension at break, which limits its range of application. A further limit to the effective exploitation of these polymers is related to their production costs, which is mostly affected by the costs of the starting feedstocks. Since the first identification of PHB, researchers have faced these issues, and several strategies to improve the processability and reduce brittleness of this polymer have been developed. These approaches range from the in vivo synthesis of PHA copolymers, to the enhancement of post-synthesis PHB-based material performances, thus the addition of additives and plasticizers, acting on the crystallization process as well as on polymer glass transition temperature. In addition, reactive polymer blending with other bio-based polymers represents a versatile approach to modulate polymer properties while preserving its biodegradability. This review examines the state of the art of PHA processing, shedding light on the green and cost-effective tailored strategies aimed at modulating and optimizing polymer performances. Pioneering examples in this field will be examined, and prospects and challenges for their exploitation will be presented. Furthermore, since the establishment of a PHA-based industry passes through the designing of cost-competitive production processes, this review will inspect reported examples assessing this economic aspect, examining the most recent progresses toward process sustainability.
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Affiliation(s)
- Rosa Turco
- Department of Chemical Sciences, University of Naples Federico II, Complesso Universitario di Monte Sant'Angelo, Naples, Italy
| | - Gabriella Santagata
- Institute for Polymers, Composites and Biomaterials, National Council of Research, Pozzuoli, Italy
| | - Iolanda Corrado
- Department of Chemical Sciences, University of Naples Federico II, Complesso Universitario di Monte Sant'Angelo, Naples, Italy
| | - Cinzia Pezzella
- Department of Agricultural Sciences, University of Naples Federico II, Portici, Italy
| | - Martino Di Serio
- Department of Chemical Sciences, University of Naples Federico II, Complesso Universitario di Monte Sant'Angelo, Naples, Italy
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Martínez-Martínez MDLA, González-Pedrajo B, Dreyfus G, Soto-Urzúa L, Martínez-Morales LJ. Phasin PhaP1 is involved in polyhydroxybutyrate granules morphology and in controlling early biopolymer accumulation in Azospirillum brasilense Sp7. AMB Express 2019; 9:155. [PMID: 31555910 PMCID: PMC6761214 DOI: 10.1186/s13568-019-0876-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Accepted: 09/09/2019] [Indexed: 11/10/2022] Open
Abstract
Phasins are amphiphilic proteins involved in the regulation of the number and size of polyhydroxybutyrate (PHB) granules. The plant growth promoting bacterium Azospirillum brasilense Sp7 accumulates high quantities of bioplastic PHB as carbon and energy source. By analyzing the genome, we identified six genes that code for proteins with a Phasin_2 domain. To understand the role of A. brasilense Sp7 PhaP1 (PhaP1Abs) on PHB synthesis, the phaP1 gene (AMK58_RS17065) was deleted. The morphology of the PHB granules was analyzed by transmission electron microscopy (TEM) and the PHB produced was quantified under three different C:N ratios in cultures subjected to null or low-oxygen transfer. The results showed that PhaP1Abs is involved in PHB granules morphology and in controlling early biopolymer accumulation. Using RT-PCR it was found that phasin genes, except phaP4, are transcribed in accordance with the C:N ratio used for the growth of A. brasilense. phaP1, phaP2 and phaP3 genes were able to respond to the growth conditions tested. This study reports the first analysis of a phasin protein in A. brasilense Sp7.
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Polyhydroxyalkanoates Synthesized by Aeromonas Species: Trends and Challenges. Polymers (Basel) 2019; 11:polym11081328. [PMID: 31405025 PMCID: PMC6722653 DOI: 10.3390/polym11081328] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 08/01/2019] [Accepted: 08/06/2019] [Indexed: 11/24/2022] Open
Abstract
The negative effects of petrochemical-derived plastics on the global environment and depletion of global fossil fuel supplies have paved the way for exploring new technologies for the production of bioplastics. Polyhydroxyalkanoates (PHAs) are considered an alternative for synthetic polymers because of their biodegradability, biocompatibility, and non-toxicity. Many bacteria have been reported to have the ability to synthesize PHAs. Among them, the Aeromonas species seem to be ideal hosts for the industrial production of these biopolyesters due to their robust growth, simple growth requirements, their ability for the synthesis of homopolymers, co-polymers, and terpolymers with unique material properties. Some Aeromonas strains were able to produce PHAs in satisfactory amounts from simple carbon sources. Efforts have been made to use genetically modified Aeromonas strains for enhanced PHAs and to obtain bacteria with modified compositions and improved properties. This review discusses the current state of knowledge of polyhydroxyalkanoates synthesized by Aeromonas species, with a special focus on their potential, challenges, and progress in PHA synthesis.
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Sagong HY, Son HF, Choi SY, Lee SY, Kim KJ. Structural Insights into Polyhydroxyalkanoates Biosynthesis. Trends Biochem Sci 2018; 43:790-805. [PMID: 30139647 DOI: 10.1016/j.tibs.2018.08.005] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Revised: 07/27/2018] [Accepted: 08/04/2018] [Indexed: 12/25/2022]
Abstract
Polyhydroxyalkanoates (PHAs) are diverse biopolyesters produced by numerous microorganisms and have attracted much attention as a substitute for petroleum-based polymers. Despite several decades of study, the detailed molecular mechanisms of PHA biosynthesis have remained unknown due to the lack of structural information on the key PHA biosynthetic enzyme PHA synthase. The recently determined crystal structure of PHA synthase, together with the structures of acetyl-coenzyme A (CoA) acetyltransferase and reductase, have changed this situation. Structural and biochemical studies provided important clues for the molecular mechanisms of each enzyme as well as the overall mechanism of PHA biosynthesis from acetyl-CoA. This new information and knowledge is expected to facilitate production of designed novel PHAs and also enhanced production of PHAs.
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Affiliation(s)
- Hye-Young Sagong
- School of Life Sciences, KNU Creative BioResearch Group, Kyungpook National University, Daegu 41566, Republic of Korea; KNU Institute for Microorganisms, Kyungpook National University, Daegu 41566, Republic of Korea
| | - Hyeoncheol Francis Son
- School of Life Sciences, KNU Creative BioResearch Group, Kyungpook National University, Daegu 41566, Republic of Korea; KNU Institute for Microorganisms, Kyungpook National University, Daegu 41566, Republic of Korea
| | - So Young Choi
- Metabolic and Biomolecular Engineering National Research Laboratory, Department of Chemical and Biomolecular Engineering (BK21 Plus Program), BioProcess Engineering Research Center, Center for Systems and Synthetic Biotechnology, and Institute for the BioCentury, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
| | - Sang Yup Lee
- Metabolic and Biomolecular Engineering National Research Laboratory, Department of Chemical and Biomolecular Engineering (BK21 Plus Program), BioProcess Engineering Research Center, Center for Systems and Synthetic Biotechnology, and Institute for the BioCentury, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea.
| | - Kyung-Jin Kim
- School of Life Sciences, KNU Creative BioResearch Group, Kyungpook National University, Daegu 41566, Republic of Korea; KNU Institute for Microorganisms, Kyungpook National University, Daegu 41566, Republic of Korea.
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Mechanistic studies of DepR in regulating FK228 biosynthesis in Chromobacterium violaceum no. 968. PLoS One 2018; 13:e0196173. [PMID: 29672625 PMCID: PMC5908139 DOI: 10.1371/journal.pone.0196173] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Accepted: 04/06/2018] [Indexed: 12/12/2022] Open
Abstract
DepR, a LysR-type transcriptional regulator encoded by the last gene of the putative min operon (orf21-20-19-depR) located at the downstream region of the anticancer agent FK228 biosynthetic gene cluster in Chromobacterium violaceum No. 968, positively regulates the biosynthesis of FK228. In this work, the mechanism underlining this positive regulation was probed by multiple approaches. Electrophoretic mobility shift assay (EMSA) and DNase I footprinting assay (DIFA) identified a conserved 35-nt DNA segment in the orf21-orf22 intergenic region where the purified recombinant DepR binds to. Quantitative reverse transcription PCR (RT-qPCR) and green fluorescent protein (GFP) promoter probe assays established that transcription of phasin gene orf22 increases in the depR deletion mutant of C. violaceum (CvΔdepR) compared to the wild-type strain. FK228 production in the orf22-overexpressed strain C. violaceum was reduced compared with the wild-type strain. DepR has two conserved cysteine residues C199 and C208 presumed to form a disulfide bridge upon sensing oxidative stress. C199X point mutations that locked DepR in a reduced conformation decreased the DNA-binding affinity of DepR; T232A or R278A mutation also had a negative impact on DNA binding of DepR. Complementation of CvΔdepR with any of those versions of depR carrying a single codon mutation was not able to restore FK228 production to the level of wild-type strain. All evidences collectively suggested that DepR positively regulates the biosynthesis of FK228 through indirect metabolic networking.
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Maestro B, Sanz JM. Polyhydroxyalkanoate-associated phasins as phylogenetically heterogeneous, multipurpose proteins. Microb Biotechnol 2017; 10:1323-1337. [PMID: 28425176 PMCID: PMC5658603 DOI: 10.1111/1751-7915.12718] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 03/19/2017] [Accepted: 03/22/2017] [Indexed: 01/01/2023] Open
Abstract
Polyhydroxyalkanoates (PHAs) are natural polyesters of increasing biotechnological importance that are synthesized by many prokaryotic organisms as carbon and energy storage compounds in limiting growth conditions. PHAs accumulate intracellularly in form of inclusion bodies that are covered with a proteinaceous surface layer (granule-associated proteins or GAPs) conforming a network-like surface of structural, metabolic and regulatory polypeptides, and configuring the PHA granules as complex and well-organized subcellular structures that have been designated as 'carbonosomes'. GAPs include several enzymes related to PHA metabolism (synthases, depolymerases and hydroxylases) together with the so-called phasins, an heterogeneous group of small-size proteins that cover most of the PHA granule and that are devoid of catalytic functions but nevertheless play an essential role in granule structure and PHA metabolism. Structurally, phasins are amphiphilic proteins that shield the hydrophobic polymer from the cytoplasm. Here, we summarize the characteristics of the different phasins identified so far from PHA producer organisms and highlight the diverse opportunities that they offer in the Biotechnology field.
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Affiliation(s)
- Beatriz Maestro
- Instituto de Biología Molecular y CelularUniversidad Miguel HernándezAv. Universidad s/nElche03202Spain
| | - Jesús M. Sanz
- Instituto de Biología Molecular y CelularUniversidad Miguel HernándezAv. Universidad s/nElche03202Spain
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Zhao H, Yao Z, Chen X, Wang X, Chen GQ. Modelling of microbial polyhydroxyalkanoate surface binding protein PhaP for rational mutagenesis. Microb Biotechnol 2017; 10:1400-1411. [PMID: 28840964 PMCID: PMC5658623 DOI: 10.1111/1751-7915.12820] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Revised: 07/07/2017] [Accepted: 07/13/2017] [Indexed: 02/05/2023] Open
Abstract
Phasins are unusual amphiphilic proteins that bind to microbial polyhydroxyalkanoate (PHA) granules in nature and show great potential for various applications in biotechnology and medicine. Despite their remarkable diversity, only the crystal structure of PhaPAh from Aeromonas hydrophila has been solved to date. Based on the structure of PhaPAh, homology models of PhaPAz from Azotobacter sp. FA‐8 and PhaPTD from Halomonas bluephagenesis TD were successfully established, allowing rational mutagenesis to be conducted to enhance the stability and surfactant properties of these proteins. PhaPAz mutants, including PhaPAzQ38L and PhaPAzQ78L, as well as PhaPTD mutants, including PhaPTDQ38M and PhaPTDQ72M, showed better emulsification properties and improved thermostability (6‐10°C higher melting temperatures) compared with their wild‐type homologues under the same conditions. Importantly, the established PhaP homology‐modelling approach, based on the high‐resolution structure of PhaPAh, can be generalized to facilitate the study of other PhaP members.
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Affiliation(s)
- Hongyu Zhao
- Center for Synthetic and Systems Biology, School of Life Sciences, Tsinghua-Peking Center for Life Sciences, Tsinghua University, Beijing, China
| | - Zhenyu Yao
- Center for Synthetic and Systems Biology, School of Life Sciences, Tsinghua-Peking Center for Life Sciences, Tsinghua University, Beijing, China
| | - Xiangbin Chen
- Center for Synthetic and Systems Biology, School of Life Sciences, Tsinghua-Peking Center for Life Sciences, Tsinghua University, Beijing, China
| | - Xinquan Wang
- MOE Laboratory of Protein Science, Beijing Advanced Innovation Center for Structural Biology, Collaborative Innovation Center for Biotherapy, School of Life Sciences, Tsinghua University, Beijing, 100084, China.,Collaborative Innovation Center for Biotherapy, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University, Chengdu, China
| | - Guo-Qiang Chen
- Center for Synthetic and Systems Biology, School of Life Sciences, Tsinghua-Peking Center for Life Sciences, Tsinghua University, Beijing, China.,Manchester Institute of Biotechnology, University of Manchester, Manchester, UK.,Center for Nano and Micro-Mechanics, Tsinghua University, Beijing, 100084, China.,MOE Key Lab for Industrial Biocatalysis, Tsinghua University, Beijing, 100084, China
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Structural Insights on PHA Binding Protein PhaP from Aeromonas hydrophila. Sci Rep 2016; 6:39424. [PMID: 28009010 PMCID: PMC5180188 DOI: 10.1038/srep39424] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Accepted: 11/22/2016] [Indexed: 02/05/2023] Open
Abstract
Phasins or PhaPs are a group of amphiphilic proteins that are found attached to the surface of microbial polyhydroxyalkanoate (PHA) granules. They have both structural and regulatory functions and can affect intracellular PHA accumulation and mediate protein folding. The molecular basis for the diverse functions of the PhaPs has not been fully understood due to the lack of the structural knowledge. Here we report the structural and biochemical studies of the PhaP cloned from Aeromonas hydrophila (PhaPAh), which is utilized in protein and tissue engineering. The crystal structure of PhaPAh was revealed to be a tetramer with 8 α-helices adopting a coiled-coil structure. Each monomer has a hydrophobic and a hydrophilic surface, rendering the surfactant properties of the PhaPAh monomer. Based on the crystal structure, we predicted three key amino acid residues and obtained mutants with enhanced stability and improved emulsification properties. The first PhaP crystal structure, as reported in this study, is an important step towards a mechanistic understanding of how PHA is formed in vivo and why PhaP has such unique surfactant properties. At the same time, it will facilitate the study of other PhaP members that may have significant biotechnological potential as bio-surfactants and amphipathic coatings.
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Phasins, Multifaceted Polyhydroxyalkanoate Granule-Associated Proteins. Appl Environ Microbiol 2016; 82:5060-7. [PMID: 27287326 DOI: 10.1128/aem.01161-16] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Phasins are the major polyhydroxyalkanoate (PHA) granule-associated proteins. They promote bacterial growth and PHA synthesis and affect the number, size, and distribution of the granules. These proteins can be classified in 4 families with distinctive characteristics. Low-resolution structural studies and in silico predictions were performed in order to elucidate the structure of different phasins. Most of these proteins share some common structural features, such as a preponderant α-helix composition, the presence of disordered regions that provide flexibility to the protein, and coiled-coil interacting regions that form oligomerization domains. Due to their amphiphilic nature, these proteins play an important structural function, forming an interphase between the hydrophobic content of PHA granules and the hydrophilic cytoplasm content. Phasins have been observed to affect both PHA accumulation and utilization. Apart from their role as granule structural proteins, phasins have a remarkable variety of additional functions. Different phasins have been determined to (i) activate PHA depolymerization, (ii) increase the expression and activity of PHA synthases, (iii) participate in PHA granule segregation, and (iv) have both in vivo and in vitro chaperone activities. These properties suggest that phasins might play an active role in PHA-related stress protection and fitness enhancement. Due to their granule binding capacity and structural flexibility, several biotechnological applications have been developed using different phasins, increasing the interest in the study of these remarkable proteins.
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Biological System as Reactor for the Production of Biodegradable Thermoplastics, Polyhydroxyalkanoates. Ind Biotechnol (New Rochelle N Y) 2016. [DOI: 10.1201/b19347-12] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] Open
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16
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Simultaneous Biosynthesis of Polyhydroxyalkanoates and Extracellular Polymeric Substance (EPS) from Crude Glycerol from Biodiesel Production by Different Bacterial Strains. Appl Biochem Biotechnol 2016; 180:1110-1127. [DOI: 10.1007/s12010-016-2155-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Accepted: 06/01/2016] [Indexed: 02/04/2023]
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Petrova O, Gorshkov V, Sergeeva I, Daminova A, Ageeva M, Gogolev Y. Alternative scenarios of starvation-induced adaptation in Pectobacterium atrosepticum. Res Microbiol 2016; 167:254-261. [DOI: 10.1016/j.resmic.2016.01.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 01/29/2016] [Accepted: 01/29/2016] [Indexed: 12/01/2022]
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18
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Characterization of binding preference of polyhydroxyalkanoate biosynthesis-related multifunctional protein PhaM from Ralstonia eutropha. Appl Microbiol Biotechnol 2016; 100:4413-21. [DOI: 10.1007/s00253-015-7225-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Revised: 12/02/2015] [Accepted: 12/05/2015] [Indexed: 10/22/2022]
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Mezzina MP, Wetzler DE, de Almeida A, Dinjaski N, Prieto MA, Pettinari MJ. A phasin with extra talents: a polyhydroxyalkanoate granule-associated protein has chaperone activity. Environ Microbiol 2014; 17:1765-76. [PMID: 25297625 DOI: 10.1111/1462-2920.12636] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Revised: 09/15/2014] [Accepted: 09/18/2014] [Indexed: 11/30/2022]
Abstract
Phasins are proteins associated to intracellular polyhydroxyalkanoate granules that affect polymer accumulation and the number and size of the granules. Previous work demonstrated that a phasin from Azotobacter sp FA-8 (PhaPAz ) had an unexpected growth-promoting and stress-protecting effect in Escherichia coli, suggesting it could have chaperone-like activities. In this work, in vitro and in vivo experiments were performed in order to investigate this possibility. PhaPAz was shown to prevent in vitro thermal aggregation of the model protein citrate synthase and to facilitate the refolding process of this enzyme after chemical denaturation. Microscopy techniques were used to analyse the subcellular localization of PhaPAz in E. coli strains and to study the role of PhaPAz in in vivo protein folding and aggregation. PhaPAz was shown to colocalize with inclusion bodies of PD, a protein that aggregates when overexpressed. A reduction in the number of inclusion bodies of PD was observed when it was coexpressed with PhaPAz or with the known chaperone GroELS. These results demonstrate that PhaPAz has chaperone-like functions both in vitro and in vivo in E. coli recombinants, and suggests that phasins could have a general protective role in natural polyhydroxyalkanoate producers.
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Affiliation(s)
- Mariela P Mezzina
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, IQUIBICEN-CONICET, Buenos Aires, Argentina
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Mezzina MP, Wetzler DE, Catone MV, Bucci H, Di Paola M, Pettinari MJ. A phasin with many faces: structural insights on PhaP from Azotobacter sp. FA8. PLoS One 2014; 9:e103012. [PMID: 25077609 PMCID: PMC4117528 DOI: 10.1371/journal.pone.0103012] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Accepted: 06/26/2014] [Indexed: 11/18/2022] Open
Abstract
Phasins are a group of proteins associated to granules of polyhydroxyalkanoates (PHAs). Apart from their structural role as part of the PHA granule cover, different structural and regulatory functions have been found associated to many of them, and several biotechnological applications have been developed using phasin protein fusions. Despite their remarkable functional diversity, the structure of these proteins has not been analyzed except in very few studies. PhaP from Azotobacter sp. FA8 (PhaPAz) is a representative of the prevailing type in the multifunctional phasin protein family. Previous work performed in our laboratory using this protein have demonstrated that it has some very peculiar characteristics, such as its stress protecting effects in recombinant Escherichia coli, both in the presence and absence of PHA. The aim of the present work was to perform a structural characterization of this protein, to shed light on its properties. Its aminoacid composition revealed that it lacks clear hydrophobic domains, a characteristic that appears to be common to most phasins, despite their lipid granule binding capacity. The secondary structure of this protein, consisting of α-helices and disordered regions, has a remarkable capacity to change according to its environment. Several experimental data support that it is a tetramer, probably due to interactions between coiled-coil regions. These structural features have also been detected in other phasins, and may be related to their functional diversity.
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Affiliation(s)
- Mariela P. Mezzina
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, IQUIBICEN-CONICET, Buenos Aires, Argentina
| | - Diana E. Wetzler
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, IQUIBICEN-CONICET, Buenos Aires, Argentina
| | - Mariela V. Catone
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, IQUIBICEN-CONICET, Buenos Aires, Argentina
| | - Hernan Bucci
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, IQUIBICEN-CONICET, Buenos Aires, Argentina
| | - Matias Di Paola
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, IQUIBICEN-CONICET, Buenos Aires, Argentina
| | - M. Julia Pettinari
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, IQUIBICEN-CONICET, Buenos Aires, Argentina
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Phasin proteins activate Aeromonas caviae polyhydroxyalkanoate (PHA) synthase but not Ralstonia eutropha PHA synthase. Appl Environ Microbiol 2014; 80:2867-73. [PMID: 24584238 DOI: 10.1128/aem.04179-13] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In this study, we performed in vitro and in vivo activity assays of polyhydroxyalkanoate (PHA) synthases (PhaCs) in the presence of phasin proteins (PhaPs), which revealed that PhaPs are activators of PhaC derived from Aeromonas caviae (PhaCAc). In in vitro assays, among the three PhaCs tested, PhaCAc was significantly activated when PhaPs were added at the beginning of polymerization (prepolymerization PhaCAc), whereas the prepolymerization PhaCRe (derived from Ralstonia eutropha) and PhaCDa (Delftia acidovorans) showed reduced activity with PhaPs. The PhaP-activated PhaCAc showed a slight shift of substrate preference toward 3-hydroxyhexanoyl-CoA (C6). PhaPAc also activated PhaCAc when it was added during polymerization (polymer-elongating PhaCAc), while this effect was not observed for PhaCRe. In an in vivo assay using Escherichia coli TOP10 as the host strain, the effect of PhaPAc expression on PHA synthesis by PhaCAc or PhaCRe was examined. As PhaPAc expression increased, PHA production was increased by up to 2.3-fold in the PhaCAc-expressing strain, whereas it was slightly increased in the PhaCRe-expressing strain. Taken together, this study provides evidence that PhaPs function as activators for PhaCAc both in vitro and in vivo but do not activate PhaCRe. This activating effect may be attributed to the new role of PhaPs in the polymerization reaction by PhaCAc.
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22
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Hiroe A, Hyakutake M, Thomson NM, Sivaniah E, Tsuge T. Endogenous ethanol affects biopolyester molecular weight in recombinant Escherichia coli. ACS Chem Biol 2013; 8:2568-76. [PMID: 24041146 DOI: 10.1021/cb400465p] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In biopolyester synthesis, polyhydroxyalkanoate (PHA) synthase (PhaC) catalyzes the polymerization of PHA in bacterial cells, followed by a chain transfer (CT) reaction in which the PHA polymer chain is transferred from PhaC to a CT agent. Accordingly, the frequency of CT reaction determines PHA molecular weight. Previous studies have shown that exogenous alcohols are effective CT agents. This study aimed to clarify the effect of endogenous ethanol as a CT agent for poly[(R)-3-hydroxybutyrate] [P(3HB)] synthesis in recombinant Escherichia coli, by comparing with that of exogenous ethanol. Ethanol supplementation to the culture medium reduced P(3HB) molecular weights by up to 56% due to ethanol-induced CT reaction. NMR analysis of P(3HB) polymers purified from the culture supplemented with (13)C-labeled ethanol showed the formation of a covalent bond between ethanol and P(3HB) chain at the carboxyl end. Cultivation without ethanol supplementation resulted in the reduction of P(3HB) molecular weight with increasing host-produced ethanol depending on culture aeration. On the other hand, production in recombinant BW25113(ΔadhE), an alcohol dehydrogenase deletion strain, resulted in a 77% increase in molecular weight. Analysis of five E. coli strains revealed that the estimated number of CT reactions was correlated with ethanol production. These results demonstrate that host-produced ethanol acts as an equally effective CT agent as exogenous ethanol, and the control of ethanol production is important to regulate the PHA molecular weight.
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Affiliation(s)
- Ayaka Hiroe
- Department
of Innovative and Engineered Materials, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8502, Japan
| | - Manami Hyakutake
- Department
of Innovative and Engineered Materials, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8502, Japan
| | - Nicholas M. Thomson
- Biological and
Soft Systems, Cavendish Laboratory, University of Cambridge, 19 JJ Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - Easan Sivaniah
- Biological and
Soft Systems, Cavendish Laboratory, University of Cambridge, 19 JJ Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - Takeharu Tsuge
- Department
of Innovative and Engineered Materials, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8502, Japan
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Application of polyhydroxyalkanoate binding protein PhaP as a bio-surfactant. Appl Microbiol Biotechnol 2011; 91:1037-47. [PMID: 21590291 DOI: 10.1007/s00253-011-3258-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2011] [Revised: 03/16/2011] [Accepted: 04/17/2011] [Indexed: 01/19/2023]
Abstract
PhaP or phasin is an amphiphilic protein located on surfaces of microbial storage polyhydroxyalkanoates granules. This study aimed to explore amphiphilic properties of PhaP for possible application as a protein surfactant. Following agents were used to conduct this study as controls including bovine serum albumin, sodium dodecyl sulfate (SDS), Tween 20, sodium oleate, a commercial liquefied detergent together with the same amount of PhaP. Among all these tested control surfactants, PhaP showed the strongest effect to form emulsions with lubricating oil, diesel, and soybean oil, respectively. PhaP emulsion stability study compared with SDS revealed that PhaP had a stronger capability to maintain a very stable emulsion layer after 30 days while SDS lost half and two-thirds of its capacity after 2 and 30 days, respectively. When PhaP was more than 200 μg/ml in the water, all liquids started to exhibit stable emulsion layers. Similar to SDS, PhaP significantly reduced the water contact angles of water on a hydrophobic film of biaxially oriented polypropylene. PhaP was thermally very stable, it showed ability to form emulsion and to bind to the surface of polyhydroxybutyrate nanoparticles after a 60- min heating process at 95 °C. It is therefore concluded that PhaP is a protein with thermally stable property for application as natural and environmentally friendly surfactant for food, cosmetic, and pharmaceutical usages.
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Horng YT, Chang KC, Chien CC, Wei YH, Sun YM, Soo PC. Enhanced polyhydroxybutyrate (PHB) productionviathe coexpressedphaCABandvgbgenes controlled by arabinose PBADpromoter inEscherichia coli. Lett Appl Microbiol 2010; 50:158-67. [DOI: 10.1111/j.1472-765x.2009.02772.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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25
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Chen GQ. A microbial polyhydroxyalkanoates (PHA) based bio- and materials industry. Chem Soc Rev 2009; 38:2434-46. [PMID: 19623359 DOI: 10.1039/b812677c] [Citation(s) in RCA: 714] [Impact Index Per Article: 47.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Biopolyesters polyhydroxyalkanoates (PHA) produced by many bacteria have been investigated by microbiologists, molecular biologists, biochemists, chemical engineers, chemists, polymer experts and medical researchers. PHA applications as bioplastics, fine chemicals, implant biomaterials, medicines and biofuels have been developed and are covered in this critical review. Companies have been established or involved in PHA related R&D as well as large scale production. Recently, bacterial PHA synthesis has been found to be useful for improving robustness of industrial microorganisms and regulating bacterial metabolism, leading to yield improvement on some fermentation products. In addition, amphiphilic proteins related to PHA synthesis including PhaP, PhaZ or PhaC have been found to be useful for achieving protein purification and even specific drug targeting. It has become clear that PHA and its related technologies are forming an industrial value chain ranging from fermentation, materials, energy to medical fields (142 references).
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Affiliation(s)
- Guo-Qiang Chen
- Dept Biological Sciences and Biotechnology, Tsinghua University, Beijing 100084, China.
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26
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Polyhydroxyalkanoate granules are complex subcellular organelles (carbonosomes). J Bacteriol 2009; 191:3195-202. [PMID: 19270094 DOI: 10.1128/jb.01723-08] [Citation(s) in RCA: 228] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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27
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Tsuge T, Watanabe S, Sato S, Hiraishi T, Abe H, Doi Y, Taguchi S. Variation in copolymer composition and molecular weight of polyhydroxyalkanoate generated by saturation mutagenesis of Aeromonas caviae PHA synthase. Macromol Biosci 2008; 7:846-54. [PMID: 17541931 DOI: 10.1002/mabi.200700023] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Amino acid substitutions at two residues downstream from the active-site histidine of polyhydroxyalkanoate (PHA) synthases are effective for changing the composition and the molecular weight of PHA. In this study, saturation mutagenesis at the position Ala505 was applied to PHA synthase (PhaCAc) from Aeromonas caviae to investigate the effects on the composition and the molecular weight of PHA synthesized in Ralstonia eutropha. The copolymer composition and molecular weight of PHA were varied by association with amino acid substitutions. There was a strong relationship between copolymer composition and PHA synthase activity of the cells. This finding will serve as a rationale for producing tailor-made PHAs.
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Affiliation(s)
- Takeharu Tsuge
- Department of Innovative and Engineered Materials, Tokyo Institute of Technology, 4259 Nagatsuta, Yokohama 226-8502, Japan.
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CHEN J, ZHANG L, CHEN J, CHEN G. Biosynthesis and Characterization of Polyhydroxyalkanoate Copolyesters in Ralstonia eutropha PHB−4 Harboring a Low-Substrate-Specificity PHA Synthase PhaC2Ps from Pseudomonas stutzeri 1317. Chin J Chem Eng 2007. [DOI: 10.1016/s1004-9541(07)60097-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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29
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Zou XH, Chen GQ. Metabolic Engineering for Microbial Production and Applications of Copolyesters Consisting of 3-Hydroxybutyrate and Medium-Chain-Length 3-Hydroxyalkanoates. Macromol Biosci 2007; 7:174-82. [PMID: 17295404 DOI: 10.1002/mabi.200600186] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Poly(hydroxyalkanoate)s (PHAs) are a class of microbially synthesized polyesters that combine biological properties, such as biocompatibility and biodegradability, and non-bioproperties such as thermoprocessability, piezoelectricity, and nonlinear optical activity. PHA monomer structures and their contents strongly affect the PHA properties. Using metabolic engineering approaches, PHA structures and contents can be manipulated to achieve controllable monomer and PHA cellular contents. This paper focuses on metabolic engineering methods to produce PHA consisting of 3-hydroxybutyrate (3HB) and medium-chain-length 3-hydroxyalkanoates (3HA) in recombinant microbial systems. This type of copolyester has mechanical and thermal properties similar to conventional plastics such as poly(propylene) and poly(ethylene terephthalate) (PET). In addition, pathways containing engineered PHA synthases have proven to be useful for enhanced PHA production with adjustable PHA monomers and contents. The applications of PHA as implant biomaterials are briefly discussed here. In the very near term, metabolic engineering will help solve many problems in promoting PHA as a new type of plastic material for many applications.
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Affiliation(s)
- Xiang Hui Zou
- Multidisciplinary Research Center, Shantou University, Shantou 515063, Guangdong, China
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Luo R, Chen J, Zhang L, Chen G. Polyhydroxyalkanoate copolyesters produced by Ralstonia eutropha PHB−4 harboring a low-substrate-specificity PHA synthase PhaC2Ps from Pseudomonas stutzeri 1317. Biochem Eng J 2006. [DOI: 10.1016/j.bej.2006.10.005] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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31
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Zheng Z, Li M, Xue XJ, Tian HL, Li Z, Chen GQ. Mutation on N-terminus of polyhydroxybutyrate synthase of Ralstonia eutropha enhanced PHB accumulation. Appl Microbiol Biotechnol 2006; 72:896-905. [PMID: 16673109 DOI: 10.1007/s00253-006-0371-0] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2005] [Revised: 02/05/2006] [Accepted: 02/07/2006] [Indexed: 10/24/2022]
Abstract
Polyhydroxyalkanoate (PHA) synthase is the central enzyme involved in the biosynthesis of PHA, a family of bacterial biodegradable polyesters. Due to its high variability, the N-terminal fragment of this enzyme was previously considered as unnecessary for a functionally active enzyme. In this study, polyhydroxybutyrate synthase from Ralstonia eutropha (PhbC(Re)) with a deletion on N-terminal 88 amino acid residues showed a significant reduced activity, as reflected by only 1.5% PHB accumulation compared with the wild type which produced 58.4% PHB of the cell dry weight. Whilst several site-specific mutagenesis results revealed the amphiphilic alpha-helix assembled by the amino acid region, D70-E88 played an important role in both maintaining the PHB synthase activity and regulating molecular weight and polydispersity of accumulated PHB homopolymer.
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Affiliation(s)
- Zhong Zheng
- MOE Laboratory of Protein Science, Department of Biological Sciences and Biotechnology, Tsinghua University, Beijing, 100084, China
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