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Hayashi Y, Arai M. Recent advances in the improvement of cyanobacterial enzymes for bioalkane production. Microb Cell Fact 2022; 21:256. [PMID: 36503511 PMCID: PMC9743570 DOI: 10.1186/s12934-022-01981-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Accepted: 12/01/2022] [Indexed: 12/14/2022] Open
Abstract
The use of biologically produced alkanes has attracted considerable attention as an alternative energy source to petroleum. In 2010, the alkane synthesis pathway in cyanobacteria was found to include two small globular proteins, acyl-(acyl carrier protein [ACP]) reductase (AAR) and aldehyde deformylating oxygenase (ADO). AAR produces fatty aldehydes from acyl-ACPs/CoAs, which are then converted by ADO to alkanes/alkenes equivalent to diesel oil. This discovery has paved the way for alkane production by genetically modified organisms. Since then, many studies have investigated the reactions catalyzed by AAR and ADO. In this review, we first summarize recent findings on structures and catalytic mechanisms of AAR and ADO. We then outline the mechanism by which AAR and ADO form a complex and efficiently transfer the insoluble aldehyde produced by AAR to ADO. Furthermore, we describe recent advances in protein engineering studies on AAR and ADO to improve the efficiency of alkane production in genetically engineered microorganisms such as Escherichia coli and cyanobacteria. Finally, the role of alkanes in cyanobacteria and future perspectives for bioalkane production using AAR and ADO are discussed. This review provides strategies for improving the production of bioalkanes using AAR and ADO in cyanobacteria for enabling the production of carbon-neutral fuels.
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Affiliation(s)
- Yuuki Hayashi
- grid.26999.3d0000 0001 2151 536XDepartment of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro, Tokyo 153-8902 Japan ,grid.26999.3d0000 0001 2151 536XEnvironmental Science Center, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033 Japan
| | - Munehito Arai
- grid.26999.3d0000 0001 2151 536XDepartment of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro, Tokyo 153-8902 Japan ,grid.26999.3d0000 0001 2151 536XDepartment of Physics, Graduate School of Science, The University of Tokyo, 3-8-1 Komaba, Meguro, Tokyo 153-8902 Japan
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Biosynthesis of alkanes/alkenes from fatty acids or derivatives (triacylglycerols or fatty aldehydes). Biotechnol Adv 2022; 61:108045. [DOI: 10.1016/j.biotechadv.2022.108045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 09/22/2022] [Accepted: 09/24/2022] [Indexed: 11/27/2022]
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Liu Y, Khusnutdinova A, Chen J, Crisante D, Batyrova K, Raj K, Feigis M, Shirzadi E, Wang X, Dorakhan R, Wang X, Stogios PJ, Yakunin AF, Sargent EH, Mahadevan R. Systems engineering of Escherichia coli for n-butane production. Metab Eng 2022; 74:98-107. [DOI: 10.1016/j.ymben.2022.10.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 10/05/2022] [Accepted: 10/08/2022] [Indexed: 10/31/2022]
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Wohlgemuth R. Selective Biocatalytic Defunctionalization of Raw Materials. CHEMSUSCHEM 2022; 15:e202200402. [PMID: 35388636 DOI: 10.1002/cssc.202200402] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Revised: 04/05/2022] [Indexed: 06/14/2023]
Abstract
Biobased raw materials, such as carbohydrates, amino acids, nucleotides, or lipids contain valuable functional groups with oxygen and nitrogen atoms. An abundance of many functional groups of the same type, such as primary or secondary hydroxy groups in carbohydrates, however, limits the synthetic usefulness if similar reactivities cannot be differentiated. Therefore, selective defunctionalization of highly functionalized biobased starting materials to differentially functionalized compounds can provide a sustainable access to chiral synthons, even in case of products with fewer functional groups. Selective defunctionalization reactions, without affecting other functional groups of the same type, are of fundamental interest for biocatalytic reactions. Controlled biocatalytic defunctionalizations of biobased raw materials are attractive for obtaining valuable platform chemicals and building blocks. The biocatalytic removal of functional groups, an important feature of natural metabolic pathways, can also be utilized in a systemic strategy for sustainable metabolite synthesis.
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Affiliation(s)
- Roland Wohlgemuth
- Institute of Molecular and Industrial Biotechnology, Lodz University of Technology Łódź, 90-537, Lodz, Poland
- Swiss Coordination Committee Biotechnology (SKB), 8002, Zurich, Switzerland
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Whitman BT, Murray CRA, Whitford DS, Paul SS, Fahlman RP, Glover MJN, Owttrim GW. Degron-mediated proteolysis of CrhR-like DEAD-box RNA helicases in cyanobacteria. J Biol Chem 2022; 298:101925. [PMID: 35413287 PMCID: PMC9117542 DOI: 10.1016/j.jbc.2022.101925] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Revised: 04/01/2022] [Accepted: 04/02/2022] [Indexed: 11/18/2022] Open
Abstract
Conditional proteolytic degradation is an irreversible and highly regulated process that fulfills crucial regulatory functions in all organisms. As proteolytic targets tend to be critical metabolic or regulatory proteins, substrates are targeted for degradation only under appropriate conditions through the recognition of an amino acid sequence referred to as a “degron”. DEAD-box RNA helicases mediate all aspects of RNA metabolism, contributing to cellular fitness. However, the mechanism by which abiotic-stress modulation of protein stability regulates bacterial helicase abundance has not been extensively characterized. Here, we provide in vivo evidence that proteolytic degradation of the cyanobacterial DEAD-box RNA helicase CrhR is conditional, being initiated by a temperature upshift from 20 to 30 °C in the model cyanobacterium, Synechocystis sp. PCC 6803. We show degradation requires a unique, highly conserved, inherently bipartite degron located in the C-terminal extension found only in CrhR-related RNA helicases in the phylum Cyanobacteria. However, although necessary, the degron is not sufficient for proteolysis, as disruption of RNA helicase activity and/or translation inhibits degradation. These results suggest a positive feedback mechanism involving a role for CrhR in expression of a crucial factor required for degradation. Furthermore, AlphaFold structural prediction indicated the C-terminal extension is a homodimerization domain with homology to other bacterial RNA helicases, and mass photometry data confirmed that CrhR exists as a dimer in solution at 22 °C. These structural data suggest a model wherein the CrhR degron is occluded at the dimerization interface but could be exposed if dimerization was disrupted by nonpermissive conditions.
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Affiliation(s)
- Brendan T Whitman
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - Cameron R A Murray
- Department of Biochemistry, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Denise S Whitford
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - Simanta S Paul
- Department of Physics, University of Alberta, Edmonton, Alberta, Canada
| | - Richard P Fahlman
- Department of Biochemistry, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Mark J N Glover
- Department of Biochemistry, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - George W Owttrim
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada.
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Abstract
Regulated proteolysis is where AAA+ ATPases (ClpX, ClpC, and ClpE) are coupled to a protease subunit (ClpP) to facilitate degradation of misfolded and native regulatory proteins in the cell. The process is intricately linked to protein quality control and homeostasis and modulates several biological processes. In streptococci, regulated proteolysis is vital to various functions, including virulence expression, competence development, bacteriocin production, biofilm formation, and stress responses. Among the various Clp ATPases, ClpX is the major one that recognizes specific amino acid residues in its substrates and delivers them to the ClpP proteolytic chamber for degradation. While multiple ClpX substrates have been identified in Escherichia coli and other bacteria, little is known about the identity of these substrates in streptococci. Here, we used a preliminary proteomic analysis to identify putative ClpX substrates using Streptococcus mutans as a model organism. SMU.961 is one such putative substrate where we identified the Glu-Lue-Gln (ELQ) motif at the C terminus that is recognized by ClpX/P. We identified several other proteins, including MecA, which also harbor ELQ and are degraded by ClpX/P. This is surprising since MecA is known to be degraded by ClpC/P in Bacillus subtilis; however, ClpX/P-mediated MecA degradation is unknown. We also identified Glu and Gln as the crucial residues for ClpX recognition. Our data indicate a species and perhaps strain-specific recognition of ELQ by streptococcal ClpX/P. At present, we do not know whether this species-dependent degradation by ClpX/P is unique to S. mutans, and we are currently examining the phenomenon in other pathogenic streptococci. IMPORTANCE ClpX/P is a major intracellular proteolytic complex that is responsible for protein quality control in the cell. ClpX, an AAA+ ATPase, distinguishes the potential substrates by recognizing short motifs at the C-terminal end of proteins and delivers the substrates for degradation by ClpP protease. The identity of these ClpX substrates, which varies greatly among bacteria, is known only for a few well-studied species. Here, we used Streptococcus mutans as a model organism to identify ClpX substrates. We found that a short motif of three residues is successfully recognized by ClpX/P. Interestingly, the motif is not present at the ultimate C-terminal end; rather it is present close to the end. This result suggests that streptococcal ClpX ATPase can recognize internal motifs.
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Basri RS, Rahman RNZRA, Kamarudin NHA, Ali MSM. Cyanobacterial aldehyde deformylating oxygenase: Structure, function, and potential in biofuels production. Int J Biol Macromol 2020; 164:3155-3162. [PMID: 32841666 DOI: 10.1016/j.ijbiomac.2020.08.162] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Revised: 08/04/2020] [Accepted: 08/20/2020] [Indexed: 11/27/2022]
Abstract
The conversion of aldehydes to valuable alkanes via cyanobacterial aldehyde deformylating oxygenase is of great interest. The availability of fossil reserves that keep on decreasing due to human exploitation is worrying, and even more troubling is the combustion emission from the fuel, which contributes to the environmental crisis and health issues. Hence, it is crucial to use a renewable and eco-friendly alternative that yields compound with the closest features as conventional petroleum-based fuel, and that can be used in biofuels production. Cyanobacterial aldehyde deformylating oxygenase (ADO) is a metal-dependent enzyme with an α-helical structure that contains di‑iron at the active site. The substrate enters the active site of every ADO through a hydrophobic channel. This enzyme exhibits catalytic activity toward converting Cn aldehyde to Cn-1 alkane and formate as a co-product. These cyanobacterial enzymes are small and easy to manipulate. Currently, ADOs are broadly studied and engineered for improving their enzymatic activity and substrate specificity for better alkane production. This review provides a summary of recent progress in the study of the structure and function of ADO, structural-based engineering of the enzyme, and highlight its potential in producing biofuels.
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Affiliation(s)
- Rose Syuhada Basri
- Enzyme and Microbial Technology Research Centre, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia; Department of Biochemistry, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia.
| | - Raja Noor Zaliha Raja Abd Rahman
- Enzyme and Microbial Technology Research Centre, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia; Department of Microbiology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia.
| | - Nor Hafizah Ahmad Kamarudin
- Enzyme and Microbial Technology Research Centre, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia; Centre of Foundation Studies for Agricultural Science, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia.
| | - Mohd Shukuri Mohamad Ali
- Enzyme and Microbial Technology Research Centre, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia; Department of Biochemistry, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia.
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