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Moanis R, Geeraert H, Van den Brande N, Hennecke U, Peeters E. Paracoccus kondratievae produces poly(3-hydroxybutyrate) under elevated temperature conditions. ENVIRONMENTAL MICROBIOLOGY REPORTS 2024; 16:e13260. [PMID: 38838099 DOI: 10.1111/1758-2229.13260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2024] [Accepted: 03/13/2024] [Indexed: 06/07/2024]
Abstract
As part of ongoing efforts to discover novel polyhydroxyalkanoate-producing bacterial species, we embarked on characterizing the thermotolerant species, Paracoccus kondratievae, for biopolymer synthesis. Using traditional chemical and thermal characterization techniques, we found that P. kondratievae accumulates poly(3-hydroxybutyrate) (PHB), reaching up to 46.8% of the cell's dry weight after a 24-h incubation at 42°C. Although P. kondratievae is phylogenetically related to the prototypical polyhydroxyalkanoate producer, Paracoccus denitrificans, we observed significant differences in the PHB production dynamics between these two Paracoccus species. Notably, P. kondratievae can grow and produce PHB at elevated temperatures ranging from 42 to 47°C. Furthermore, P. kondratievae reaches its peak PHB content during the early stationary growth phase, specifically after 24 h of growth in a flask culture. This is then followed by a decline in the later stages of the stationary growth phase. The depolymerization observed in this growth phase is facilitated by the abundant presence of the PhaZ depolymerase enzyme associated with PHB granules. We observed the highest PHB levels when the cells were cultivated in a medium with glycerol as the sole carbon source and a carbon-to-nitrogen ratio of 10. Finally, we found that PHB production is induced as an osmotic stress response, similar to other polyhydroxyalkanoate-producing species.
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Affiliation(s)
- Radwa Moanis
- Research Group of Microbiology, Department of Bioengineering Sciences, Vrije Universiteit Brussel, Brussels, Belgium
- Faculty of Sciences, Botany and Microbiology Department, Damanhour University, Damanhour, Egypt
| | - Hannelore Geeraert
- Research Group of Physical Chemistry and Polymer Science, Vrije Universiteit Brussel, Brussels, Belgium
| | - Niko Van den Brande
- Research Group of Physical Chemistry and Polymer Science, Vrije Universiteit Brussel, Brussels, Belgium
| | - Ulrich Hennecke
- Research Group of Organic Chemistry, Department of Chemistry and Department of Bioengineering Sciences, Vrije Universiteit Brussel, Brussels, Belgium
| | - Eveline Peeters
- Research Group of Microbiology, Department of Bioengineering Sciences, Vrije Universiteit Brussel, Brussels, Belgium
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Wang J, Huang J, Xiao X, Zhang D, Zhang Z, Zhou Z, Liu S. (R)−3-hydroxybutyrate production by Burkholderia cepacia in the cathode chamber of ethanol-producing microbial fuel cells. Biochem Eng J 2022. [DOI: 10.1016/j.bej.2022.108581] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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3
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Wu D, Zhao Z, Zhang L, Wang L, Zhou Y. Metagenomic assembled genomes unravel purple non‑sulfur bacteria (PNSB) involved in integrating C, N, P biotransformation. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 830:154591. [PMID: 35318065 DOI: 10.1016/j.scitotenv.2022.154591] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 02/17/2022] [Accepted: 03/11/2022] [Indexed: 06/14/2023]
Abstract
Purple non‑sulfur bacteria (PNSB) based bioprocess has been developed to remove carbon, nitrogen and phosphorus from wastewater. However, the interactions of various bioconversion of carbon (C), nitrogen (N) and phosphorus (P) are not completely clear. In this study, a genome-centric metagenomic approach was employed to delineate the shift in microbial community structures and functional genes under light and dark conditions. Seven and 22 metagenomic assembled genomes (MAGs) were recovered from samples in light and dark conditions, accounting for a substantial portion of microbes. Under light, Rhodopseudomonas palustris promoted complex metabolic processes and interactions for C, N and P conversions. Burkholderia contaminans was discovered as new potential organisms for simultaneous C, N and P removal. Metagenomics analysis confirmed genes involved in the synthesis of glycogen, poly-β-hydroxybutyrate, poly-P, amino acids and carotenoids in R. palustris. The substrate transformation mechanisms and potential pathways were proposed according to the detected metabolites. Our findings provided insights into a new biological system with simultaneous C, N and P bioconversions, and improved the understanding of interactions among the key populations.
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Affiliation(s)
- Dan Wu
- Advanced Environmental Biotechnology Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, Singapore 637141, Singapore
| | - Zelong Zhao
- Liaoning Key Lab of Germplasm Improvement and Fine Seed Breeding of Marine Aquatic animals, Liaoning Ocean and Fisheries Science Research Institute, Dalian, Liaoning 116023, PR China
| | - Liang Zhang
- Advanced Environmental Biotechnology Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, Singapore 637141, Singapore
| | - Li Wang
- Advanced Environmental Biotechnology Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, Singapore 637141, Singapore
| | - Yan Zhou
- Advanced Environmental Biotechnology Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, Singapore 637141, Singapore; School of Civil and Environmental Engineering, Nanyang Technological University, Singapore 639798, Singapore.
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Characterization of an intracellular poly(3-hydroxyalkanoate) depolymerase from the soil bacterium, Pseudomonas putida LS46. Polym Degrad Stab 2020. [DOI: 10.1016/j.polymdegradstab.2020.109127] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Chek MF, Kim SY, Mori T, Tan HT, Sudesh K, Hakoshima T. Asymmetric Open-Closed Dimer Mechanism of Polyhydroxyalkanoate Synthase PhaC. iScience 2020; 23:101084. [PMID: 32388399 PMCID: PMC7214940 DOI: 10.1016/j.isci.2020.101084] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 04/01/2020] [Accepted: 04/15/2020] [Indexed: 12/15/2022] Open
Abstract
Biodegradable polyester polyhydroxyalkanoate (PHA) is a promising bioplastic material for industrial use as a replacement for petroleum-based plastics. PHA synthase PhaC forms an active dimer to polymerize acyl moieties from the substrate acyl-coenzyme A (CoA) into PHA polymers. Here we present the crystal structure of the catalytic domain of PhaC from Chromobacterium sp. USM2, bound to CoA. The structure reveals an asymmetric dimer, in which one protomer adopts an open conformation bound to CoA, whereas the other adopts a closed conformation in a CoA-free form. The open conformation is stabilized by the asymmetric dimerization and enables PhaC to accommodate CoA and also to create the product egress path. The bound CoA molecule has its β-mercaptoethanolamine moiety extended into the active site with the terminal SH group close to active center Cys291, enabling formation of the reaction intermediate by acylation of Cys291. Crystal structure of PhaCCs-CAT bound to coenzyme A A unique asymmetric open-closed dimer Restructuring of the CAP subdomain provides a cleft toward the active site The cleft enables the substrate entry and the product egress
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Affiliation(s)
- Min Fey Chek
- Structural Biology Laboratory, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192, Japan
| | - Sun-Yong Kim
- Structural Biology Laboratory, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192, Japan
| | - Tomoyuki Mori
- Structural Biology Laboratory, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192, Japan
| | - Hua Tiang Tan
- School of Biological Sciences, Universiti Sains Malaysia, 11800 Penang, Malaysia
| | - Kumar Sudesh
- School of Biological Sciences, Universiti Sains Malaysia, 11800 Penang, Malaysia
| | - Toshio Hakoshima
- Structural Biology Laboratory, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192, Japan.
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Wang Z, Woo SG, Yao Y, Cheng HH, Wu YJ, Criddle CS. Nitrogen removal as nitrous oxide for energy recovery: Increased process stability and high nitrous yields at short hydraulic residence times. WATER RESEARCH 2020; 173:115575. [PMID: 32058151 DOI: 10.1016/j.watres.2020.115575] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 01/29/2020] [Accepted: 01/30/2020] [Indexed: 06/10/2023]
Abstract
The Coupled Aerobic-anoxic Nitrous Decomposition Operation (CANDO) is a two-stage process for nitrogen removal and resource recovery: in the first, ammonia is oxidized to nitrite in an aerobic bioreactor; in the second, oxidation of polyhydroxyalkanoate (PHA) drives reduction of nitrite to nitrous oxide (N2O) which is stripped for use as a biogas oxidant. Because ammonia oxidation is well-studied, tests of CANDO to date have focused on N2O production in anaerobic/anoxic sequencing batch reactors. In these reactors, nitrogen is provided as nitrite; PHA is produced from acetate or other dissolved COD, and PHA oxidation is coupled to N2O production from nitrite. In a pilot-scale study, N2O recovery was affected by COD/N ratio, total cycle time, and relative time periods for PHA synthesis and N2O production. In follow-up bench-scale studies, different reactor cycle times were used to investigate these operational parameters. Increasing COD/N ratio improved nitrite removal and increased biosolids concentration. Shortening the anaerobic phase prevented fermentation of PHA and improved its utilization. Efficient PHA synthesis and utilization in the anaerobic phase correlated with high N2O production in the anoxic phase. Shortening the anoxic phase prevented reduction of N2O to N2. By shortening both phases, total cycle time was reduced from 24 to 12 h. This optimized operation enabled increased biomass concentrations, increased N2O yields (from 71 to 87%), increased N loading rates (from 0.1 to 0.25 kg N/m3-d), and shorter hydraulic residence times (from 10 to 2 days). Long-term changes in operational performance for the different bioreactor systems tested were generally similar despite significant differences in microbial community structure. Long-term operation at short anaerobic phases selected for a glycogen-accumulating community dominated by a Defluviicoccus-related strain.
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Affiliation(s)
- Zhiyue Wang
- Department of Civil and Environmental Engineering, Stanford University, Stanford, CA, USA; U.S. National Science Foundation Engineering Research Center for Re-inventing the Nation's Urban Water Infrastructure (ReNUWIt), USA
| | - Sung-Geun Woo
- Department of Civil and Environmental Engineering, Stanford University, Stanford, CA, USA; U.S. National Science Foundation Engineering Research Center for Re-inventing the Nation's Urban Water Infrastructure (ReNUWIt), USA
| | - Yinuo Yao
- Department of Civil and Environmental Engineering, Stanford University, Stanford, CA, USA; U.S. National Science Foundation Engineering Research Center for Re-inventing the Nation's Urban Water Infrastructure (ReNUWIt), USA
| | - Hai-Hsuan Cheng
- Department of Environmental Engineering, National Cheng Kung University, Tainan, Taiwan
| | - Yi-Ju Wu
- Department of Environmental Engineering, National Cheng Kung University, Tainan, Taiwan
| | - Craig S Criddle
- Department of Civil and Environmental Engineering, Stanford University, Stanford, CA, USA; U.S. National Science Foundation Engineering Research Center for Re-inventing the Nation's Urban Water Infrastructure (ReNUWIt), USA.
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Complete Genome Sequence and Annotation of the Paracoccus pantotrophus Type Strain DSM 2944. Microbiol Resour Announc 2020; 9:9/1/e01290-19. [PMID: 31896641 PMCID: PMC6940293 DOI: 10.1128/mra.01290-19] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Paracoccus spp. are metabolically versatile alphaproteobacteria able to perform heterotrophic and chemoautotrophic growth. This study describes the whole-genome sequence of the Paracoccus pantotrophus type strain DSM 2944 (ATCC 35512, LMD 82.5, GB17). The genome sequence revealed the presence of a complete phaZ phaC phaP phaR gene cluster related to polyhydroxyalkanoate metabolism. Paracoccus spp. are metabolically versatile alphaproteobacteria able to perform heterotrophic and chemoautotrophic growth. This study describes the whole-genome sequence of the Paracoccus pantotrophus type strain DSM 2944 (ATCC 35512, LMD 82.5, GB17). The genome sequence revealed the presence of a complete phaZ phaC phaP phaR gene cluster related to polyhydroxyalkanoate metabolism.
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Kandasamy R, Rajasekaran M, Venkatesan SK, Uddin M. New Trends in the Biomanufacturing of Green Surfactants: Biobased Surfactants and Biosurfactants. ACS SYMPOSIUM SERIES 2019. [DOI: 10.1021/bk-2019-1329.ch011] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Ramani Kandasamy
- Biomolecules and Biocatalysis Laboratory, Department of Biotechnology, School of Bioengineering, SRM Institute of Science and Technology, Kattankulathur 603 203, Tamil Nadu, India
| | - Muneeswari Rajasekaran
- Biomolecules and Biocatalysis Laboratory, Department of Biotechnology, School of Bioengineering, SRM Institute of Science and Technology, Kattankulathur 603 203, Tamil Nadu, India
| | - Swathi Krishnan Venkatesan
- Biomolecules and Biocatalysis Laboratory, Department of Biotechnology, School of Bioengineering, SRM Institute of Science and Technology, Kattankulathur 603 203, Tamil Nadu, India
| | - Maseed Uddin
- Biomolecules and Biocatalysis Laboratory, Department of Biotechnology, School of Bioengineering, SRM Institute of Science and Technology, Kattankulathur 603 203, Tamil Nadu, India
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Samantaray PK, Madras G, Bose S. Microbial Biofilm Membranes for Water Remediation and Photobiocatalysis. ACS SYMPOSIUM SERIES 2019. [DOI: 10.1021/bk-2019-1329.ch014] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Paresh Kumar Samantaray
- Centre for BioSystems Science and Engineering, Indian Institute of Science, Bangalore, Karnataka 560012, India
- Department of Materials Engineering, Indian Institute of Science, Bangalore, Karnataka 560012, India
| | - Giridhar Madras
- Department of Chemical Engineering, Indian Institute of Science, Bangalore, Karnataka 560012, India
| | - Suryasarathi Bose
- Department of Materials Engineering, Indian Institute of Science, Bangalore, Karnataka 560012, India
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Yadav TC, Srivastava AK, Mishra P, Singh D, Raghuwanshi N, Singh NK, Singh AK, Tiwari SK, Prasad R, Pruthi V. Electrospinning: An Efficient Biopolymer-Based Micro- and Nanofibers Fabrication Technique. ACS SYMPOSIUM SERIES 2019. [DOI: 10.1021/bk-2019-1329.ch010] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Tara Chand Yadav
- Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee - 247667, Uttarakhand, India
| | - Amit Kumar Srivastava
- Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee - 247667, Uttarakhand, India
| | - Purusottam Mishra
- Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee - 247667, Uttarakhand, India
| | - Divya Singh
- Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee - 247667, Uttarakhand, India
| | - Navdeep Raghuwanshi
- Vaccine Formulation & Research Center, Gennova (Emcure) Biopharmaceuticals Limited, Pune - 411057, Maharashtra, India
| | - Nitin Kumar Singh
- Department of Environment Science and Engineering, Marwadi Education Foundations Group of Institutions, Rajkot - 360003, Gujarat, India
| | - Amit Kumar Singh
- Department of Biochemistry, University of Allahabad, Allahabad, 211002 India
| | | | - Ramasare Prasad
- Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee - 247667, Uttarakhand, India
| | - Vikas Pruthi
- Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee - 247667, Uttarakhand, India
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Balakrishna Pillai A, Jaya Kumar A, Kumarapillai H. Enhanced production of poly(3-hydroxybutyrate) in recombinant Escherichia coli and EDTA-microwave-assisted cell lysis for polymer recovery. AMB Express 2018; 8:142. [PMID: 30182189 PMCID: PMC6123327 DOI: 10.1186/s13568-018-0672-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2018] [Accepted: 08/31/2018] [Indexed: 11/12/2022] Open
Abstract
Poly(3-hydroxybutyrate) (PHB) is a bacterial polymer of great commercial importance due to its properties similar to polypropylene. With an aim to develop a recombinant system for economical polymer production, PHB biosynthesis genes from Bacillus aryabhattai PHB10 were cloned in E. coli. The recombinant cells accumulated a maximum level of 6.22 g/L biopolymer utilizing glycerol in shake flasks. The extracted polymer was confirmed as PHB by GC-MS and NMR analyses. The polymer showed melting point at 171 °C, thermal stability in a temperature range of 0-140 °C and no weight loss up to 200 °C. PHB extracted from sodium hypochlorite lysed cells had average molecular weight of 143.108 kDa, polydispersity index (PDI) 1.81, tensile strength of 14.2 MPa and an elongation at break of 7.65%. This is the first report on high level polymer accumulation in recombinant E. coli solely expressing PHB biosynthesis genes from a Bacillus sp. As an alternative to sodium hypochlorite cell lysis mediated polymer extraction, the effect of combined treatment with ethylenediaminetetraacetic acid and microwave was studied which attained 93.75% yield. The polymer recovered through this method was 97.21% pure, showed 2.9-fold improvement in molecular weight and better PDI. The procedure is simple, with minimum polymer damage and more eco-friendly than the sodium hypochlorite lysis method.
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Affiliation(s)
- Aneesh Balakrishna Pillai
- Environmental Biology Laboratory, Rajiv Gandhi Centre for Biotechnology (RGCB) Poojappura, Thycaud P. O., Thiruvananthapuram, Kerala 695014 India
| | - Arjun Jaya Kumar
- Environmental Biology Laboratory, Rajiv Gandhi Centre for Biotechnology (RGCB) Poojappura, Thycaud P. O., Thiruvananthapuram, Kerala 695014 India
| | - Harikrishnan Kumarapillai
- Environmental Biology Laboratory, Rajiv Gandhi Centre for Biotechnology (RGCB) Poojappura, Thycaud P. O., Thiruvananthapuram, Kerala 695014 India
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Structure of polyhydroxyalkanoate (PHA) synthase PhaC from Chromobacterium sp. USM2, producing biodegradable plastics. Sci Rep 2017; 7:5312. [PMID: 28706283 PMCID: PMC5509742 DOI: 10.1038/s41598-017-05509-4] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Accepted: 06/05/2017] [Indexed: 11/08/2022] Open
Abstract
Polyhydroxyalkanoate (PHA) is a promising candidate for use as an alternative bioplastic to replace petroleum-based plastics. Our understanding of PHA synthase PhaC is poor due to the paucity of available three-dimensional structural information. Here we present a high-resolution crystal structure of the catalytic domain of PhaC from Chromobacterium sp. USM2, PhaC Cs -CAT. The structure shows that PhaC Cs -CAT forms an α/β hydrolase fold comprising α/β core and CAP subdomains. The active site containing Cys291, Asp447 and His477 is located at the bottom of the cavity, which is filled with water molecules and is covered by the partly disordered CAP subdomain. We designated our structure as the closed form, which is distinct from the recently reported catalytic domain from Cupriavidus necator (PhaC Cn -CAT). Structural comparison showed PhaC Cn -CAT adopting a partially open form maintaining a narrow substrate access channel to the active site, but no product egress. PhaC Cs -CAT forms a face-to-face dimer mediated by the CAP subdomains. This arrangement of the dimer is also distinct from that of the PhaC Cn -CAT dimer. These findings suggest that the CAP subdomain should undergo a conformational change during catalytic activity that involves rearrangement of the dimer to facilitate substrate entry and product formation and egress from the active site.
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Li F, Zhang C, Liu Y, Liu D, Xia H, Chen S. Efficient production of ( R )-3-hydroxybutyric acid by Pseudomonas sp. DS1001a and its extracellular poly(3-hydroxybutyrate) depolymerase. Process Biochem 2016. [DOI: 10.1016/j.procbio.2015.12.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Wang Z, Mao H, Liu H, Su T, Jiang H. Optimization of medium composition for 3-hydroxycarboxylic acid production by Pseudomonas mendocina-biodegraded polyhydroxybutyrate. Biotechnol Appl Biochem 2014; 62:260-7. [PMID: 24919602 DOI: 10.1002/bab.1257] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2014] [Accepted: 06/03/2014] [Indexed: 11/09/2022]
Abstract
We optimized the culture medium for 3-hydroxycarboxylic acid production by Pseudomonas mendocina DS-04-T-biodegraded polyhydroxybutyrate (PHB) using the Plackett-Burman design, steepest ascent method, and Box-Behnken design. The optimized concentrations of the constituents of the culture medium were as follows: PHB (7.57 g/L), NH4 Cl (5.0 g/L), KH2 PO4 (2.64 g/L), Na2 HPO4 ·12H2 O (12 g/L), MgSO4 ·7H2 O (0.5 g/L), and CaCl2 ·2H2 O (5 mg/L). The yield of 3-hydroxycarboxylic acid obtained using the optimized culture medium was 56.8 ± 1.64%, which was 2.5-fold higher than that obtained when the unoptimized culture medium was used.
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Affiliation(s)
- Zhanyong Wang
- College of Chemistry, Chemical Engineering and Environmental Engineering, Liaoning Shihua University, Fushun, People's Republic of China
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Jendrossek D, Pfeiffer D. New insights in the formation of polyhydroxyalkanoate granules (carbonosomes) and novel functions of poly(3-hydroxybutyrate). Environ Microbiol 2014; 16:2357-73. [PMID: 24329995 DOI: 10.1111/1462-2920.12356] [Citation(s) in RCA: 173] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2013] [Revised: 11/27/2013] [Accepted: 12/05/2013] [Indexed: 12/18/2022]
Abstract
The metabolism of polyhydroxybutyrate (PHB) and related polyhydroxyalkanoates (PHAs) has been investigated by many groups for about three decades, and good progress was obtained in understanding the mechanisms of biosynthesis and biodegradation of this class of storage molecules. However, the molecular events that happen at the onset of PHB synthesis and the details of the initiation of PHB/PHA granule formation, as well as the complex composition of the proteinaceous surface layer of PHB/PHA granules, have only recently come into the focus of research and were not reviewed yet. In this contribution, we summarize the progress in understanding the initiation and formation of the PHA granule complex at the example of Ralstonia eutropha H16 (model organism of PHB-accumulating bacteria). Where appropriate, we include information on PHA granules of Pseudomonas putida as a representative species for medium-chain-length PHA-accumulating bacteria. We suggest to replace the previous micelle mode of PHB granule formation by the Scaffold Model in which the PHB synthase initiation complex is bound to the bacterial nucleoid. In the second part, we highlight data on other forms of PHB: oligo-PHB with ≈100 to 200 3-hydroxybutyrate (3HB) units and covalently bound PHB (cPHB) are unrelated in function to storage PHB but are presumably present in all living organisms, and therefore must be of fundamental importance.
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3-Hydroxybutyrate oligomer hydrolase and 3-hydroxybutyrate dehydrogenase participate in intracellular polyhydroxybutyrate and polyhydroxyvalerate degradation in Paracoccus denitrificans. Appl Environ Microbiol 2013; 80:986-93. [PMID: 24271169 DOI: 10.1128/aem.03396-13] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Genes encoding 3-hydroxybutyrate oligomer hydrolase (PhaZc) and 3-hydroxybutyrate dehydrogenase (Hbd) were isolated from Paracoccus denitrificans. PhaZc and Hbd were overproduced as His-tagged proteins in Escherichia coli and purified by affinity and gel filtration chromatography. Purified His-tagged proteins had molecular masses of 31 kDa and 120 kDa (a tetramer of 29-kDa subunits). The His-tagged PhaZc hydrolyzed not only 3-hydroxybutyrate oligomers but also 3-hydroxyvalerate oligomers. The His-tagged Hbd catalyzed the dehydrogenation of 3-hydroxyvalerate as well as 3-hydroxybutyrate. When both enzymes were included in the same enzymatic reaction system with 3-hydroxyvalerate dimer, sequential reactions occurred, suggesting that PhaZc and Hbd play an important role in the intracellular degradation of poly(3-hydroxyvalerate). When the phaZc gene was disrupted in P. denitrificans by insertional inactivation, the mutant strain lost PhaZc activity. When the phaZc-disrupted P. denitrificans was complemented with phaZc, PhaZc activity was restored. These results suggest that P. denitrificans carries a single phaZc gene. Disruption of the phaZc gene in P. denitrificans affected the degradation rate of PHA.
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Albuquerque MGE, Carvalho G, Kragelund C, Silva AF, Barreto Crespo MT, Reis MAM, Nielsen PH. Link between microbial composition and carbon substrate-uptake preferences in a PHA-storing community. ISME JOURNAL 2012; 7:1-12. [PMID: 22810062 DOI: 10.1038/ismej.2012.74] [Citation(s) in RCA: 89] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The microbial community of a fermented molasses-fed sequencing batch reactor (SBR) operated under feast and famine conditions for production of polyhydroxyalkanoates (PHAs) was identified and quantified through a 16 S rRNA gene clone library and fluorescence in situ hybridization (FISH). The microbial enrichment was found to be composed of PHA-storing populations (84% of the microbial community), comprising members of the genera Azoarcus, Thauera and Paracoccus. The dominant PHA-storing populations ensured the high functional stability of the system (characterized by high PHA-storage efficiency, up to 60% PHA content). The fermented molasses contained primarily acetate, propionate, butyrate and valerate. The substrate preferences were determined by microautoradiography-FISH and differences in the substrate-uptake capabilities for the various probe-defined populations were found. The results showed that in the presence of multiple substrates, microbial populations specialized in different substrates were selected, thereby co-existing in the SBR by adapting to different niches. Azoarcus and Thauera, primarily consumed acetate and butyrate, respectively. Paracoccus consumed a broader range of substrates and had a higher cell-specific substrate uptake. The relative species composition and their substrate specialization were reflected in the substrate removal rates of different volatile fatty acids in the SBR reactor.
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Affiliation(s)
- Maria G E Albuquerque
- REQUIMTE/CQFB, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Lisboa, Portugal
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Rey DA, Strickland AD, Kirui D, Niamsiri N, Batt CA. In vitro self-assembly of gold nanoparticle-coated poly(3-hydroxybutyrate) granules exhibiting plasmon-induced thermo-optical enhancements. ACS APPLIED MATERIALS & INTERFACES 2010; 2:1804-1810. [PMID: 20565131 DOI: 10.1021/am100306m] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Polyhydroxyalkanoate (PHA) synthase attached to gold nanoparticles (AuNP) produce poly(3-hydroxybutyrate) (PHB) upon the addition of 3-hydroxybutyrate-CoA, and then coalesce to form micrometer-sized AuNP-coated PHB granules. These AuNP-coated PHB granules are potential theranostic agents that have enhanced imaging capabilities and are capable of heating upon near-infrared laser irradiation. The AuNP-coated PHB exhibited 11-fold enhancement in surface-enhanced Raman scattering over particles prior polymerization. Stained AuNP-coated PHB exhibited a 6-fold enhancement in fluorescence intensity as well as a 1.3-fold decrease in photobleaching rate compared to PHB granules alone. The granules were also shown to emit heat when illuminated at 808 nm with a 3.9-fold increase in heating rate compared to particles alone.
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Trainer MA, Capstick D, Zachertowska A, Lam KN, Clark SRD, Charles TC. Identification and characterization of the intracellular poly-3-hydroxybutyrate depolymerase enzyme PhaZ of Sinorhizobium meliloti. BMC Microbiol 2010; 10:92. [PMID: 20346169 PMCID: PMC2867953 DOI: 10.1186/1471-2180-10-92] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2009] [Accepted: 03/27/2010] [Indexed: 11/23/2022] Open
Abstract
Background S. meliloti forms indeterminate nodules on the roots of its host plant alfalfa (Medicago sativa). Bacteroids of indeterminate nodules are terminally differentiated and, unlike their non-terminally differentiated counterparts in determinate nodules, do not accumulate large quantities of Poly-3-hydroxybutyrate (PHB) during symbiosis. PhaZ is in intracellular PHB depolymerase; it represents the first enzyme in the degradative arm of the PHB cycle in S. meliloti and is the only enzyme in this half of the PHB cycle that remains uncharacterized. Results The S. meliloti phaZ gene was identified by in silico analysis, the ORF was cloned, and a S. meliloti phaZ mutant was constructed. This mutant exhibited increased PHB accumulation during free-living growth, even when grown under non-PHB-inducing conditions. The phaZ mutant demonstrated no reduction in symbiotic capacity; interestingly, analysis of the bacteroids showed that this mutant also accumulated PHB during symbiosis. This mutant also exhibited a decreased capacity to tolerate long-term carbon starvation, comparable to that of other PHB cycle mutants. In contrast to other PHB cycle mutants, the S. meliloti phaZ mutant did not exhibit any decrease in rhizosphere competitiveness; however, this mutant did exhibit a significant increase in succinoglycan biosynthesis. Conclusions S. meliloti bacteroids retain the capacity to synthesize PHB during symbiosis; interestingly, accumulation does not occur at the expense of symbiotic performance. phaZ mutants are not compromised in their capacity to compete for nodulation in the rhizosphere, perhaps due to increased succinoglycan production resulting from upregulation of the succinoglycan biosynthetic pathway. The reduced survival capacity of free-living cells unable to access their accumulated stores of PHB suggests that PHB is a crucial metabolite under adverse conditions.
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Affiliation(s)
- Maria A Trainer
- Department of Biology, University of Waterloo, 200 University Ave W, Waterloo, ON N2L 3G1, Canada
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Degradation of Natural and Artificial Poly[(R)-3-hydroxyalkanoate]s: From Biodegradation to Hydrolysis. ACTA ACUST UNITED AC 2009. [DOI: 10.1007/978-3-642-03287-5_12] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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21
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Identification and characterization of a novel intracellular poly(3-hydroxybutyrate) depolymerase from Bacillus megaterium. Appl Environ Microbiol 2009; 75:5290-9. [PMID: 19561190 DOI: 10.1128/aem.00621-09] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A gene that codes for a novel intracellular poly(3-hydroxybutyrate) (PHB) depolymerase, designated PhaZ1, has been identified in the genome of Bacillus megaterium. A native PHB (nPHB) granule-binding assay showed that purified soluble PhaZ1 had strong affinity for nPHB granules. Turbidimetric analyses revealed that PhaZ1 could rapidly degrade nPHB granules in vitro without the need for protease pretreatment of the granules to remove surface proteins. Notably, almost all the final hydrolytic products produced from the in vitro degradation of nPHB granules by PhaZ1 were 3-hydroxybutyric acid (3HB) monomers. Unexpectedly, PhaZ1 could also hydrolyze denatured semicrystalline PHB, with the generation of 3HB monomers. The disruption of the phaZ1 gene significantly affected intracellular PHB mobilization during the PHB-degrading stage in B. megaterium, as demonstrated by transmission electron microscopy and the measurement of the PHB content. These results indicate that PhaZ1 is functional in intracellular PHB mobilization in vivo. Some of these features, which are in striking contrast with those of other known nPHB granule-degrading PhaZs, may provide an advantage for B. megaterium PhaZ1 in fermentative production of the biotechnologically valuable chiral compound (R)-3HB.
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Grage K, Jahns AC, Parlane N, Palanisamy R, Rasiah IA, Atwood JA, Rehm BHA. Bacterial Polyhydroxyalkanoate Granules: Biogenesis, Structure, and Potential Use as Nano-/Micro-Beads in Biotechnological and Biomedical Applications. Biomacromolecules 2009; 10:660-9. [DOI: 10.1021/bm801394s] [Citation(s) in RCA: 203] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Katrin Grage
- Institute of Molecular Biosciences, Massey University, Private Bag 11222, Palmerston North 4442, New Zealand and Hopkirk Research Institute, Massey University, Private Bag 11222, Palmerston North 4442, New Zealand
| | - Anika C. Jahns
- Institute of Molecular Biosciences, Massey University, Private Bag 11222, Palmerston North 4442, New Zealand and Hopkirk Research Institute, Massey University, Private Bag 11222, Palmerston North 4442, New Zealand
| | - Natalie Parlane
- Institute of Molecular Biosciences, Massey University, Private Bag 11222, Palmerston North 4442, New Zealand and Hopkirk Research Institute, Massey University, Private Bag 11222, Palmerston North 4442, New Zealand
| | - Rajasekaran Palanisamy
- Institute of Molecular Biosciences, Massey University, Private Bag 11222, Palmerston North 4442, New Zealand and Hopkirk Research Institute, Massey University, Private Bag 11222, Palmerston North 4442, New Zealand
| | - Indira A. Rasiah
- Institute of Molecular Biosciences, Massey University, Private Bag 11222, Palmerston North 4442, New Zealand and Hopkirk Research Institute, Massey University, Private Bag 11222, Palmerston North 4442, New Zealand
| | - Jane A. Atwood
- Institute of Molecular Biosciences, Massey University, Private Bag 11222, Palmerston North 4442, New Zealand and Hopkirk Research Institute, Massey University, Private Bag 11222, Palmerston North 4442, New Zealand
| | - Bernd H. A. Rehm
- Institute of Molecular Biosciences, Massey University, Private Bag 11222, Palmerston North 4442, New Zealand and Hopkirk Research Institute, Massey University, Private Bag 11222, Palmerston North 4442, New Zealand
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23
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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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Kadouri D, Jurkevitch E, Okon Y, Castro-Sowinski S. Ecological and Agricultural Significance of Bacterial Polyhydroxyalkanoates. Crit Rev Microbiol 2008; 31:55-67. [PMID: 15986831 DOI: 10.1080/10408410590899228] [Citation(s) in RCA: 138] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Polyhydroxyalkanoates (PHAs) are a group of carbon andenergy storage compounds that are accumulated during suboptimal growth by many bacteria, and intracellularly deposited in the form of inclusion bodies. Accumulation of PHAs is thought to be used by bacteria to increase survival and stress tolerance in changing environments, and in competitive settings where carbon and energy sources may be limited, such as those encountered in the soil and the rhizosphere. Understanding the role that PHAs play as internal storage polymers is of fundamental importance in microbial ecology, and holds great potential for the improvement of bacterial inoculants for plants and soils. This review summarizes the current knowledge on the ecological function of PHAs, and their strategic role as survival factors in microorganisms under varying environmental stress is emphasized. It also explores the phylogeny of the PHA cycle enzymes, PHA synthase, and PHA depolymerase, suggesting that PHA accumulation was earlier acquired and maintained during evolution, thus contributing to microbial survival in the environment.
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Affiliation(s)
- Daniel Kadouri
- Department of Plant Pathology and Microbiology, Faculty of Agricultural, Food and Environmental Quality Sciences, The Hebrew University of Jerusalem, Rehovot, Israel
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25
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Poly(3-hydroxybutyrate) (PHB) depolymerase PhaZa1 is involved in mobilization of accumulated PHB in Ralstonia eutropha H16. Appl Environ Microbiol 2007; 74:1058-63. [PMID: 18156336 DOI: 10.1128/aem.02342-07] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The recently finished genome sequence of Ralstonia eutropha H16 harbors nine genes that are thought to encode functions for intracellular depolymerization (mobilization) of storage poly(3-hydroxybutyrate) (PHB). Based on amino acid similarities, the gene products belong to four classes (PhaZa1 to PhaZa5, PhaZb, PhaZc, and PhaZd1/PhaZd2). However, convincing direct evidence for the in vivo roles of the gene products is poor. In this study, we selected four candidate genes (phaZa1, phaZb, phaZc, and phaZd1) representing the four classes and investigated the physiological function of the gene products (i) with recombinant Escherichia coli strains and (ii) with R. eutropha null mutants. Evidence for weak but significant PHB depolymerase activity was obtained only for PhaZa1. The physiological roles of the other potential PHB depolymerases remain uncertain.
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Jendrossek D. Peculiarities of PHA granules preparation and PHA depolymerase activity determination. Appl Microbiol Biotechnol 2007; 74:1186-96. [PMID: 17318541 DOI: 10.1007/s00253-007-0860-9] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2006] [Revised: 01/22/2007] [Accepted: 01/24/2007] [Indexed: 11/26/2022]
Abstract
An extensive amount of knowledge on biochemistry of poly(3-hydroxyalkanoic acid) (PHA) synthesis and on its biodegradation has accumulated during the last two decades. Numerous genes encoding enzymes involved in the formation of PHA and in PHA degradation (PHA depolymerases) were cloned and characterized from many microorganisms. A large variety of methods exists for determination of PHA depolymerase activity and for preparation of the polymeric substrate (PHA). Unfortunately, results obtained with these different methods cannot be compared directly because they highly depend on the assay method applied and on the history of PHA granules preparation. In this contribution, the peculiarities, advantages, disadvantages and limitations of existing PHA depolymerase assay methods are described.
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Affiliation(s)
- Dieter Jendrossek
- Institut für Mikrobiologie, Universität Stuttgart, Allmandring 31, 70550 Stuttgart, Germany.
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27
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Yamada M, Yamashita K, Wakuda A, Ichimura K, Maehara A, Maeda M, Taguchi S. Autoregulator protein PhaR for biosynthesis of polyhydroxybutyrate [P(3HB)] possibly has two separate domains that bind to the target DNA and P(3HB): Functional mapping of amino acid residues responsible for DNA binding. J Bacteriol 2007; 189:1118-27. [PMID: 17122335 PMCID: PMC1797304 DOI: 10.1128/jb.01550-06] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2006] [Accepted: 11/14/2006] [Indexed: 11/20/2022] Open
Abstract
PhaR from Paracoccus denitrificans functions as a repressor or autoregulator of the expression of genes encoding phasin protein (PhaP) and PhaR itself, both of which are components of polyhydroxyalkanoate (PHA) granules (A. Maehara, S. Taguchi, T. Nishiyama, T. Yamane, and Y. Doi, J. Bacteriol. 184:3992-4002, 2002). PhaR is a unique regulatory protein in that it also has the ability to bind tightly to an effector molecule, PHA polyester. In this study, by using a quartz crystal microbalance, we obtained direct evidence that PhaR binds to the target DNA and poly[(R)-3-hydroxybutyrate] [P(3HB)], one of the PHAs, at the same time. To identify the PhaR amino acid residues responsible for DNA binding, deletion and PCR-mediated random point mutation experiments were carried out with the gene encoding the PhaR protein. PhaR point mutants with decreased DNA-binding abilities were efficiently screened by an in vivo monitoring assay system coupled with gene expression of green fluorescent protein in Escherichia coli. DNA-binding abilities of the wild-type and mutants of recombinant PhaR expressed in E. coli were evaluated using a gel shift assay and a surface plasmon resonance analysis. These experiments revealed that basic amino acids and a tyrosine in the N-terminal region, which is highly conserved among PhaR homologs, are responsible for DNA binding. However, most of the mutants with decreased DNA-binding abilities were unaffected in their ability to bind P(3HB), strongly suggesting that PhaR has two separate domains capable of binding to the target DNA and P(3HB).
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Affiliation(s)
- Miwa Yamada
- Graduate School of Engineering, Hokkaido University, N13W8, Sapporo, Hokkaido 060-8628, Japan
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28
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Gebauer B, Jendrossek D. Assay of poly(3-hydroxybutyrate) depolymerase activity and product determination. Appl Environ Microbiol 2006; 72:6094-100. [PMID: 16957234 PMCID: PMC1563597 DOI: 10.1128/aem.01184-06] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Two methods for accurate poly(3-hydroxybutyrate) (PHB) depolymerase activity determination and quantitative and qualitative hydrolysis product determination are described. The first method is based on online determination of NaOH consumption rates necessary to neutralize 3-hydroxybutyric acid (3HB) and/or 3HB oligomers produced during the hydrolysis reaction and requires a pH-stat apparatus equipped with a software-controlled microliter pump for rapid and accurate titration. The method is universally suitable for hydrolysis of any type of polyhydroxyalkanoate or other molecules with hydrolyzable ester bonds, allows the determination of hydrolysis rates of as low as 1 nmol/min, and has a dynamic capacity of at least 6 orders of magnitude. By applying this method, specific hydrolysis rates of native PHB granules isolated from Ralstonia eutropha H16 were determined for the first time. The second method was developed for hydrolysis product identification and is based on the derivatization of 3HB oligomers into bromophenacyl derivates and separation by high-performance liquid chromatography. The method allows the separation and quantification of 3HB and 3HB oligomers up to the octamer. The two methods were applied to investigate the hydrolysis of different types of PHB by selected PHB depolymerases.
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Affiliation(s)
- Birgit Gebauer
- Institut für Mikrobiologie, Universität Stuttgart, Allmandring 31, 70550 Stuttgart, Germany
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29
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Tseng CL, Chen HJ, Shaw GC. Identification and characterization of the Bacillus thuringiensis phaZ gene, encoding new intracellular poly-3-hydroxybutyrate depolymerase. J Bacteriol 2006; 188:7592-9. [PMID: 16936025 PMCID: PMC1636284 DOI: 10.1128/jb.00729-06] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A gene that codes for a novel intracellular poly-3-hydroxybutyrate (PHB) depolymerase has now been identified in the genome of Bacillus thuringiensis subsp. israelensis ATCC 35646. This gene, previously annotated as a hypothetical 3-oxoadipate enol-lactonase (PcaD) gene and now designated phaZ, encodes a protein that shows no significant similarity with any known PHB depolymerase. Purified His-tagged PhaZ could efficiently degrade trypsin-activated native PHB granules as well as artificial amorphous PHB granules and release 3-hydroxybutyrate monomer as a hydrolytic product, but it could not hydrolyze denatured semicrystalline PHB. In contrast, purified His-tagged PcaD of Pseudomonas putida was unable to degrade trypsin-activated native PHB granules and artificial amorphous PHB granules. The B. thuringiensis PhaZ was inactive against p-nitrophenylpalmitate, tributyrin, and triolein. Sonication supernatants of the wild-type B. thuringiensis cells exhibited a PHB-hydrolyzing activity in vitro, whereas those prepared from a phaZ mutant lost this activity. The phaZ mutant showed a higher PHB content than the wild type at late stationary phase of growth in a nutrient-rich medium, indicating that this PhaZ can function as a PHB depolymerase in vivo. PhaZ contains a lipase box-like sequence (G-W-S(102)-M-G) but lacks a signal peptide. A purified His-tagged S102A variant had lost the PHB-hydrolyzing activity. Taken together, these results indicate that B. thuringiensis harbors a new type of intracellular PHB depolymerase.
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Affiliation(s)
- Chi-Ling Tseng
- Institute of Biochemistry and Molecular Biology, School of Life Science, National Yang-Ming University, Taipei 112, Taiwan, Republic of China
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30
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Abe T, Kobayashi T, Saito T. Properties of a novel intracellular poly(3-hydroxybutyrate) depolymerase with high specific activity (PhaZd) in Wautersia eutropha H16. J Bacteriol 2005; 187:6982-90. [PMID: 16199568 PMCID: PMC1251622 DOI: 10.1128/jb.187.20.6982-6990.2005] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A novel intracellular poly(3-hydroxybutyrate) (PHB) depolymerase (PhaZd) of Wautersia eutropha (formerly Ralstonia eutropha) H16 which shows similarity with the catalytic domain of the extracellular PHB depolymerase in Ralstonia pickettii T1 was identified. The positions of the catalytic triad (Ser190-Asp266-His330) and oxyanion hole (His108) in the amino acid sequence of PhaZd deduced from the nucleotide sequence roughly accorded with those of the extracellular PHB depolymerase of R. pickettii T1, but a signal peptide, a linker domain, and a substrate binding domain were missing. The PhaZd gene was cloned and the gene product was purified from Escherichia coli. The specific activity of PhaZd toward artificial amorphous PHB granules was significantly greater than that of other known intracellular PHB depolymerase or 3-hydroxybutyrate (3HB) oligomer hydrolases of W. eutropha H16. The enzyme degraded artificial amorphous PHB granules and mainly released various 3-hydroxybutyrate oligomers. PhaZd distributed nearly equally between PHB inclusion bodies and the cytosolic fraction. The amount of PHB was greater in phaZd deletion mutant cells than the wild-type cells under various culture conditions. These results indicate that PhaZd is a novel intracellular PHB depolymerase which participates in the mobilization of PHB in W. eutropha H16 along with other PHB depolymerases.
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Affiliation(s)
- Tomoko Abe
- Laboratory of Molecular Microbiology, Department of Biological Sciences, Faculty of Science, Kanagawa University, 2946 Tsuchiya, Hiratsuka, Kanagawa 259-1293, Japan
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Kobayashi T, Saito T. Catalytic triad of intracellular poly(3-hydroxybutyrate) depolymerase (PhaZ1) in Ralstonia eutropha H16. J Biosci Bioeng 2005; 96:487-92. [PMID: 16233560 DOI: 10.1016/s1389-1723(03)70136-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2003] [Accepted: 09/08/2003] [Indexed: 11/17/2022]
Abstract
The amino acid sequence of an intracellular poly[D(-)-3-hydroxybutyrate] (PHB) depolymerase (PhaZ1) from Ralstonia eutropha H16 was compared with the sequences of various proteins using the BLAST search. It showed a number of matches including with intracellular PHB depolymerases, conserved hypothetical proteins, and PHB synthases. From an alignment of these proteins, we constructed nine mutants: C87A, S118A, H120Q, C183A, C183S, D355A, D356A, C370A, and H388Q. The C183A, D355A, and H388Q mutants lost their activities, but C183S and the other mutants did not. C183, D355, and H388 in PhaZ1 were positioned similarly to the amino acids of the catalytic triad of PHB synthase. These results indicated that C183, D355, and H388 make up the catalytic triad of PhaZ1.
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Affiliation(s)
- Teruyuki Kobayashi
- Laboratory of Molecular Microbiology, Department of Biological Sciences, Faculty of Science, Kanagawa University, 2946 Tsuchiya, Hiratsuka, Kanagawa 259-1293, Japan
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Kojima T, Nishiyama T, Maehara A, Ueda S, Nakano H, Yamane T. Expression profiles of polyhydroxyalkanoate synthesis-related genes in Paracoccus denitrificans. J Biosci Bioeng 2005; 97:45-53. [PMID: 16233588 DOI: 10.1016/s1389-1723(04)70164-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2003] [Accepted: 10/18/2003] [Indexed: 10/26/2022]
Abstract
A facultative methylotrophic bacterium, Paracoccus denitrificans can synthesize polyhydroxyalkanoate acids (PHA) from various alcohols. Recently, six genes, phaA, B, C, P, R, and Z, related to PHA synthesis have been cloned and characterized. PHA synthesis and the expression of phaA, B, C, P, R, and Z in P. denitrificans were examined at the transcriptional and translational levels under both nitrogen-sufficient and nitrogen-deficient conditions. The results showed that PHA synthesis is not regulated at the mRNA or protein level in phaA, B, and C. We also observed the condensation of acetyl-coenzyme A (acetyl-CoA) in the cells by high-performance liquid chromatography (HPLC). The results suggest that the amount of acetyl-CoA would regulate PHA synthesis. Finally, we discuss a possible regulation mechanism for PHA synthesis in P. denitrificans.
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Affiliation(s)
- Takaaki Kojima
- Laboratory of Molecular Biotechnology, Graduate School of Biological and Agricultural Sciences, Nagoya University, Nagoya 464-8601, Japan
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Kobayashi T, Uchino K, Abe T, Yamazaki Y, Saito T. Novel intracellular 3-hydroxybutyrate-oligomer hydrolase in Wautersia eutropha H16. J Bacteriol 2005; 187:5129-35. [PMID: 16030206 PMCID: PMC1196019 DOI: 10.1128/jb.187.15.5129-5135.2005] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Wautersia eutropha H16 (formerly Ralstonia eutropha) mobilizes intracellularly accumulated poly(3-hydroxybutyrate) (PHB) with intracellular poly(3-hydroxybutyrate) depolymerases. In this study, a novel intracellular 3-hydroxybutyrate-oligomer hydrolase (PhaZc) gene was cloned and overexpressed in Escherichia coli. Then PhaZc was purified and characterized. Immunoblot analysis with polyclonal antiserum against PhaZc revealed that most PhaZc is present in the cytosolic fraction and a small amount is present in the poly(3-hydroxybutyrate) inclusion bodies of W. eutropha. PhaZc degraded various 3-hydroxybutyrate oligomers at a high specific activity and artificial amorphous poly(3-hydroxybutyrate) at a lower specific activity. Native PHB granules and semicrystalline PHB were not degraded by PhaZc. A PhaZ deletion mutation enhanced the deposition of PHB in the logarithmic phase in nutrient-rich medium. PhaZc differs from the hydrolases of W. eutropha previously reported and is a novel type of intracellular 3-hydroxybutyrate-oligomer hydrolase, and it participates in the mobilization of PHB along with other hydrolases.
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Affiliation(s)
- Teruyuki Kobayashi
- Laboratory of Molecular Microbiology, Department of Biological Sciences, Faculty of Science, Kanagawa University, 2946 Tsuchiya, Hiratsuka, Kanagawa 259-1293, Japan
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Pötter M, Steinbüchel A. Poly(3-hydroxybutyrate) granule-associated proteins: impacts on poly(3-hydroxybutyrate) synthesis and degradation. Biomacromolecules 2005; 6:552-60. [PMID: 15762612 DOI: 10.1021/bm049401n] [Citation(s) in RCA: 170] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Polyhydroxyalkanoates (PHAs) represent a group of biopolymers that are synthesized by many bacteria as storage compounds and deposited as insoluble cytoplasmic inclusions. Because they have many putative technical and medical applications, PHAs may play an important role in human life in the future. Therefore, for academic interest the bacterial PHA metabolism has been studied in much detail. In the past decade much new and unexpected information about the metabolism of PHA in bacteria became available. Aspects of the biogenesis of PHA granules in bacteria become more and more important in the literature. Several enzymes, proteins, and mechanisms of regulation are involved in PHA biosynthesis and PHA granule biogenesis. The intention of this review is to give an overview about our current knowledge of the structure of the PHA granule surface and the PHA granule-associated proteins involved in biogenesis and degradation. The focus is on the PHA synthases, the intracellular PHA depolymerases, the phasins, and the transcriptional regulator PhaR, which are the main actors in biosynthesis and intracellular degradation of PHAs and formation of PHA granules. In addition, putative applications of PHA granules and PHA granule-associated proteins in nanotechnology are discussed.
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Affiliation(s)
- Markus Pötter
- Institut für Molekulare Mikrobiologie und Biotechnologie, Westfälische Wilhelms-Universität Münster, Corrensstrasse 3, 48149 Münster, Germany
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Handrick R, Reinhardt S, Kimmig P, Jendrossek D. The "intracellular" poly(3-hydroxybutyrate) (PHB) depolymerase of Rhodospirillum rubrum is a periplasm-located protein with specificity for native PHB and with structural similarity to extracellular PHB depolymerases. J Bacteriol 2004; 186:7243-53. [PMID: 15489436 PMCID: PMC523223 DOI: 10.1128/jb.186.21.7243-7253.2004] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Rhodospirillum rubrum possesses a putative intracellular poly(3-hydroxybutyrate) (PHB) depolymerase system consisting of a soluble PHB depolymerase, a heat-stable activator, and a 3-hydroxybutyrate dimer hydrolase (J. M. Merrick and M. Doudoroff, J. Bacteriol. 88:60-71, 1964). In this study we reinvestigated the soluble R. rubrum PHB depolymerase (PhaZ1). It turned out that PhaZ1 is a novel type of PHB depolymerase with unique properties. Purified PhaZ1 was specific for amorphous short-chain-length polyhydroxyalkanoates (PHA) such as native PHB, artificial PHB, and oligomer esters of (R)-3-hydroxybutyrate with 3 or more 3-hydroxybutyrate units. Atactic PHB, (S)-3-hydroxybutyrate oligomers, medium-chain-length PHA, and lipase substrates (triolein, tributyrin) were not hydrolyzed. The PHB depolymerase structural gene (phaZ1) was cloned. Its deduced amino acid sequence (37,704 Da) had no significant similarity to those of intracellular PHB depolymerases of Wautersia eutropha or of other PHB-accumulating bacteria. PhaZ1 was found to have strong amino acid homology with type-II catalytic domains of extracellular PHB depolymerases, and Ser(42), Asp(138), and His(178) were identified as catalytic-triad amino acids, with Ser(42) as the putative active site. Surprisingly, the first 23 amino acids of the PHB depolymerase previously assumed to be intracellular revealed features of classical signal peptides, and Edman sequencing of purified PhaZ1 confirmed the functionality of the predicted cleavage site. Extracellular PHB depolymerase activity was absent, and analysis of cell fractions unequivocally showed that PhaZ1 is a periplasm-located enzyme. The previously assumed intracellular activator/depolymerase system is unlikely to have a physiological function in PHB mobilization in vivo. A second gene, encoding the putative true intracellular PHB depolymerase (PhaZ2), was identified in the genome sequence of R. rubrum.
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Affiliation(s)
- René Handrick
- Institut für Mikrobiologie, Universität Stuttgart, Allmandring 31, 70550 Stuttgart, Germany
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Rehm BHA. Polyester synthases: natural catalysts for plastics. Biochem J 2003; 376:15-33. [PMID: 12954080 PMCID: PMC1223765 DOI: 10.1042/bj20031254] [Citation(s) in RCA: 462] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2003] [Accepted: 09/04/2003] [Indexed: 11/17/2022]
Abstract
Polyhydroxyalkanoates (PHAs) are biopolyesters composed of hydroxy fatty acids, which represent a complex class of storage polyesters. They are synthesized by a wide range of different Gram-positive and Gram-negative bacteria, as well as by some Archaea, and are deposited as insoluble cytoplasmic inclusions. Polyester synthases are the key enzymes of polyester biosynthesis and catalyse the conversion of (R)-hydroxyacyl-CoA thioesters to polyesters with the concomitant release of CoA. These soluble enzymes turn into amphipathic enzymes upon covalent catalysis of polyester-chain formation. A self-assembly process is initiated resulting in the formation of insoluble cytoplasmic inclusions with a phospholipid monolayer and covalently attached polyester synthases at the surface. Surface-attached polyester synthases show a marked increase in enzyme activity. These polyester synthases have only recently been biochemically characterized. An overview of these recent findings is provided. At present, 59 polyester synthase structural genes from 45 different bacteria have been cloned and the nucleotide sequences have been obtained. The multiple alignment of the primary structures of these polyester synthases show an overall identity of 8-96% with only eight strictly conserved amino acid residues. Polyester synthases can been assigned to four classes based on their substrate specificity and subunit composition. The current knowledge on the organization of the polyester synthase genes, and other genes encoding proteins related to PHA metabolism, is compiled. In addition, the primary structures of the 59 PHA synthases are aligned and analysed with respect to highly conserved amino acids, and biochemical features of polyester synthases are described. The proposed catalytic mechanism based on similarities to alpha/beta-hydrolases and mutational analysis is discussed. Different threading algorithms suggest that polyester synthases belong to the alpha/beta-hydrolase superfamily, with a conserved cysteine residue as catalytic nucleophile. This review provides a survey of the known biochemical features of these unique enzymes and their proposed catalytic mechanism.
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Affiliation(s)
- Bernd H A Rehm
- Institut für Molekulare Mikrobiologie und Biotechnologie der Westfälischen Wilhelms-Universität Münster, Corrensstrasse 3, 48149 Münster, Germany.
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Hiraishi A, Khan ST. Application of polyhydroxyalkanoates for denitrification in water and wastewater treatment. Appl Microbiol Biotechnol 2003; 61:103-9. [PMID: 12655451 DOI: 10.1007/s00253-002-1198-y] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2002] [Revised: 11/05/2002] [Accepted: 11/08/2002] [Indexed: 11/26/2022]
Abstract
Application of polyhydroxyalkanoates (PHAs) and related biodegradable polymers has gained momentum in various areas of biotechnology. A promising application that started appearing in the past decade is the use of PHAs as the solid substrate for denitrification of water and wastewater. This type of denitrification, termed here "solid-phase denitrification", has several advantages over the conventional system supplemented with liquid organic substrate. PHAs serve not only as constant sources of reducing power for denitrification but also as solid matrices favorable for development of microbial films. In addition, in contrast to conventional processes, the use of PHAs has no potential risk of release of dissolved organic carbon with the resultant deterioration of effluent water quality. If the production cost of PHAs can be brought down, its application to the denitrification process will become economically more promising. A number of PHA-degrading denitrifying bacteria have been isolated and characterized from activated sludge and continuous flow-bed reactors for denitrification with PHAs. Most of these isolates have been assigned phylogenetically to members of beta-Proteobacteria, especially those of the family Comamonadaceae. The metabolic and regulatory relationships between PHA degradation and denitrification, and the interactive relationship between PHA-degrading cells and the solid surface structure are important subjects awaiting future studies, which would provide a new insight into our comprehensive understanding of the solid-phase denitrification process.
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Affiliation(s)
- A Hiraishi
- Department of Ecological Engineering, Toyohashi University of Technology, Toyohashi, 441-8580, Toyohashi, Japan.
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Abstract
Polyesters such as poly(3-hydroxybutyrate) (PHB) or other polyhydroxyalkanoates (PHA) have attracted commercial and academic interest as new biodegradable materials. The ability to degrade PHA is widely distributed among bacteria and fungi and depends on the secretion of specific extracellular PHA depolymerases (e-PHA depolymerases), which are carboxyesterases (EC 3.1.1.75 and EC 3.1.1.76), and on the physical state of the polymer (amorphous or crystalline). This contribution provides a summary of the biochemical and molecular biological characteristics of e-PHA depolymerases and focuses on the intracellular mobilization of storage PHA by intracellular PHA depolymerases (i-PHA depolymerases) of PHA-accumulating bacteria. The importance of different assay systems for PHA depolymerase activity is also discussed.
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Affiliation(s)
- Dieter Jendrossek
- Institut für Mikrobiologie, Allmandring 31, D-70550 Stuttgart, Germany.
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Maehara A, Taguchi S, Nishiyama T, Yamane T, Doi Y. A repressor protein, PhaR, regulates polyhydroxyalkanoate (PHA) synthesis via its direct interaction with PHA. J Bacteriol 2002; 184:3992-4002. [PMID: 12081972 PMCID: PMC135160 DOI: 10.1128/jb.184.14.3992-4002.2002] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2002] [Accepted: 04/04/2002] [Indexed: 11/20/2022] Open
Abstract
Phasins (PhaP) are predominantly polyhydroxyalkanoate (PHA) granule-associated proteins that positively affect PHA synthesis. Recently, we reported that the phaR gene, which is located downstream of phaP in Paracoccus denitrificans, codes for a negative regulator involved in PhaP expression. In this study, DNase I footprinting revealed that PhaR specifically binds to two regions located upstream of phaP and phaR, suggesting that PhaR plays a role in the regulation of phaP expression as well as autoregulation. Many TGC-rich sequences were found in upstream elements recognized by PhaR. PhaR in the crude lysate of recombinant Escherichia coli was able to rebind specifically to poly[(R)-3-hydroxybutyrate] [P(3HB)] granules. Furthermore, artificial P(3HB) granules and 3HB oligomers caused the dissociation of PhaR from PhaR-DNA complexes, but native PHA granules, which were covered with PhaP or other nonspecific proteins, did not cause the dissociation. These results suggest that PhaR is able to sense both the onset of PHA synthesis and the enlargement of the granules through direct binding to PHA. However, free PhaR is probably unable to sense the mature PHA granules which are already covered sufficiently with PhaP and/or other proteins. An in vitro expression experiment revealed that phaP expression was repressed by the addition of PhaR and was derepressed by the addition of P(3HB). Based on these findings, we present here a possible model accounting for the PhaR-mediated mechanism of PHA synthesis. Widespread distribution of PhaR homologs in short-chain-length PHA-producing bacteria suggests a common and important role of PhaR-mediated regulation of PHA synthesis.
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Affiliation(s)
- Akira Maehara
- Polymer Chemistry Laboratory, RIKEN Institute, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan
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Ueda S, Sano K, Gao D, Tomihari N, Yamane T, Endo I. Purification and properties of D-(-)-3-hydroxybutyrate oligomer hydrolase of Paracoccus denitrificans. FEMS Microbiol Lett 2002; 206:179-84. [PMID: 11814660 DOI: 10.1111/j.1574-6968.2002.tb11006.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
D-(-)-3-Hydroxybutyrate (3HB) oligomer hydrolase was purified from Paracoccus denitrificans. The enzyme was a monomeric protein with an approximate molecular mass of 31 kDa. The isoelectric point of the enzyme was 5.2. Optimum temperature and pH were 35-40 degrees C and 8.0, respectively. The enzyme activity was not affected by sulfhydryl reagents but strongly inhibited by serine proteinase inhibitors. Both 3HB trimer and 3HB dimer were hydrolyzed by the enzyme, indicating that the enzyme is not 3HB dimer hydrolase but 3HB oligomer hydrolase. para-Nitrophenyl esters of short-chain fatty acids were also hydrolyzed by the enzyme. 3HB dimer was hydrolyzed somewhat faster than 3HB trimer. The level of the enzyme activity was almost constant, irrespective of carbon sources for the bacterial growth and of the cultivation conditions.
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Affiliation(s)
- Shunsaku Ueda
- Department of Bioproductive Science, Faculty of Agriculture, Utsunomiya University, Japan.
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Haruhisa S, Mari S, Terumi S. Cloning of an intracellular d(−)-3-hydroxybutyrate-oligomer hydrolase gene from Ralstonia eutropha H16 and identification of the active site serine residue by site-directed mutagenesis. J Biosci Bioeng 2002. [DOI: 10.1016/s1389-1723(02)80128-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Maehara A, Doi Y, Nishiyama T, Takagi Y, Ueda S, Nakano H, Yamane T. PhaR, a protein of unknown function conserved among short-chain-length polyhydroxyalkanoic acids producing bacteria, is a DNA-binding protein and represses Paracoccus denitrificans phaP expression in vitro. FEMS Microbiol Lett 2001; 200:9-15. [PMID: 11410342 DOI: 10.1111/j.1574-6968.2001.tb10685.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
A putative regulatory protein, PhaR, which was identified in the polyhydroxyalkanoic acid synthetic locus (phaZCPR) in Paracoccus denitrificans, was investigated. The PhaR protein purified from a recombinant Escherichia coli was estimated to be 22 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, being consistent with the mass calculated from the nucleotide sequence. The molecular mass was determined to be 93 kDa by size-exclusion chromatography, suggesting that the protein formed a tetramer. A gel mobility shift assay showed that PhaR specifically bound to the intergenic region of phaC--phaP. In a cell-free protein synthesis system using E. coli S30 extract, the expression of the phaP gene was repressed by the addition of purified PhaR. These results suggest that PhaR is a DNA-binding protein and may play a role in the regulation of phaP gene expression.
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Affiliation(s)
- A Maehara
- Department of Biological Mechanisms and Functions, Graduate School of Bioagricultural Sciences, Nagoya University, Japan
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