1
|
Zhao J, Shi F, Huang Y, Hou Y, Jin P, Hu SQ. Total Biosynthesis of Circular Bacteriocins by Merging the Genetic Engineering and Enzymatic Catalysis. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2024; 72:20547-20556. [PMID: 39137283 DOI: 10.1021/acs.jafc.4c04749] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/15/2024]
Abstract
Circular bacteriocins are known for their structural stability and effective antimicrobial properties, positioning them as potential natural food preservatives. However, their widespread application is impeded by restricted availability. This research developed a total biosynthesis platform for circular bacteriocins, with a focus on AS-48 by involving recombinant production of the linear precursor in Escherichia coli, followed by enzymatic cyclization of the precursor into cyclic AS-48 using the ligase butelase-1 in vitro. An important discovery is that, aside from fusion tags, the C-terminal motif LE and LEKKK also could affect the expression yield of the precursor. This biosynthesis platform is both versatile and high-yielding, achieving yields of 10-20 mg/L of AS-48. Importantly, the biosynthetic AS-48 exhibited a secondary structure and antimicrobial activities comparable to those of the native molecules. As such, this work proposes an effective synthetic approach for circular bacteriocins, facilitating their advancement and application in the food industry.
Collapse
Affiliation(s)
- Jinsong Zhao
- School of Food Science and Engineering, South China University of Technology, Guangzhou 510640, China
- College of Agricultural and Food Sciences, Zhejiang A&F University, Hangzhou 311300, China
| | - Fan Shi
- School of Food Science and Engineering, South China University of Technology, Guangzhou 510640, China
| | - Yanbo Huang
- State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou 510640, China
| | - Yi Hou
- State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou 510640, China
| | - Peng Jin
- College of Agricultural and Food Sciences, Zhejiang A&F University, Hangzhou 311300, China
| | - Song-Qing Hu
- School of Food Science and Engineering, South China University of Technology, Guangzhou 510640, China
| |
Collapse
|
2
|
Uniacke-Lowe S, Collins FWJ, Hill C, Ross RP. Bioactivity Screening and Genomic Analysis Reveals Deep-Sea Fish Microbiome Isolates as Sources of Novel Antimicrobials. Mar Drugs 2023; 21:444. [PMID: 37623725 PMCID: PMC10456417 DOI: 10.3390/md21080444] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 07/10/2023] [Accepted: 07/31/2023] [Indexed: 08/26/2023] Open
Abstract
With the increase in antimicrobial resistance and the subsequent demand for novel therapeutics, the deep-sea fish microbiome can be a relatively untapped source of antimicrobials, including bacteriocins. Previously, bacterial isolates were recovered from the gut of deep-sea fish sampled from the Atlantic Ocean.In this study, we used in vitro methods to screen a subset of these isolates for antimicrobial activity, and subsequently mined genomic DNA from isolates of interest for bacteriocin and other antimicrobial metabolite genes. We observed antimicrobial activity against foodborne pathogens, including Staphylococcus aureus, Listeria monocytogenes, Enterococcus faecalis and Micrococcus luteus. In total, 147 candidate biosynthetic gene clusters were identified in the genomic sequences, including 35 bacteriocin/RiPP-like clusters. Other bioactive metabolite genes detected included non-ribosomal peptide synthases (NRPS), polyketide synthases (PKS; Types 1 and 3), beta-lactones and terpenes. Moreover, four unique bacteriocin gene clusters were annotated and shown to encode novel peptides: a class IIc bacteriocin, two class IId bacteriocins and a class I lanthipeptide (LanM subgroup). Our dual in vitro and in silico approach allowed for a more comprehensive understanding of the bacteriocinogenic potential of these deep-sea isolates and an insight into the antimicrobial molecules that they may produce.
Collapse
Affiliation(s)
- Shona Uniacke-Lowe
- Department of Microbiology, University College Cork, T12 K8AF Cork, Ireland
- APC Microbiome Ireland, T12 K8AF Cork, Ireland
- Teagasc Food Research Centre, P61 C996 Fermoy, Ireland
| | | | - Colin Hill
- Department of Microbiology, University College Cork, T12 K8AF Cork, Ireland
- APC Microbiome Ireland, T12 K8AF Cork, Ireland
| | - R Paul Ross
- Department of Microbiology, University College Cork, T12 K8AF Cork, Ireland
- APC Microbiome Ireland, T12 K8AF Cork, Ireland
| |
Collapse
|
3
|
Liu F, van Heel AJ, Kuipers OP. Leader- and Terminal Residue Requirements for Circularin A Biosynthesis Probed by Systematic Mutational Analyses. ACS Synth Biol 2023; 12:852-862. [PMID: 36857413 PMCID: PMC10028692 DOI: 10.1021/acssynbio.2c00661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/02/2023]
Abstract
Circularin A is a circular bacteriocin belonging to a subgroup of the ribosomally synthesized and post-translationally modified peptide (RiPP) superfamily. The post-translational biosynthesis of circular bacteriocins primarily consists of leader cleavage, core peptide circularization, and bacteriocin secretion. However, none of these processes have been fully elucidated due to the complex biosynthesis of such bacteriocins and the lack of homology to the functions of other known biosynthetic enzymes. In this study, we investigated the leader- and terminal residue requirements for the biosynthesis of circularin A by systematic mutational analyses, including the mutational effects of variable leader lengths, as well as site-directed substitutions of residues at positions near the leader cleavage site and the circularization site. Results show that the leader with only one Met residue, the shortest leader possible, is sufficient to produce mature circularin A; helix-forming short-sidechain hydrophobic residues are required at positions Val1 and Ala2 of the N-terminus to form active peptide derivatives, indicating the possible steric hindrance effect at these two positions; and an aromatic residue is required at the C-terminal Tyr69 position to produce a mature circular derivative. However, the requirements for residues at position Ala68 are much more relaxed relative to the positions of Val1 and Ala2, since even substitution with the largest possible residue, i.e., tryptophan, still allows the generation of an active Ala68Trp derivative. Our findings provide new perspectives for the biosynthesis of this short-leader circular bacteriocin, which enables the application of circular bacteriocin biosynthesis in rational modified peptide engineering.
Collapse
Affiliation(s)
- Fangfang Liu
- Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, 9747 AG Groningen, The Netherlands
| | - Auke J van Heel
- Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, 9747 AG Groningen, The Netherlands
| | - Oscar P Kuipers
- Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, 9747 AG Groningen, The Netherlands
| |
Collapse
|
4
|
Liu F, van Heel AJ, Chen J, Kuipers OP. Functional production of clostridial circularin A in Lactococcus lactis NZ9000 and mutational analysis of its aromatic and cationic residues. Front Microbiol 2022; 13:1026290. [PMID: 36504829 PMCID: PMC9726714 DOI: 10.3389/fmicb.2022.1026290] [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: 08/23/2022] [Accepted: 11/07/2022] [Indexed: 11/24/2022] Open
Abstract
Circular bacteriocins, also known as bacterial head-to-tail cyclized peptides, are a subgroup of ribosomally synthesized and post-translationally modified peptides (RiPPs). Compared with their conventional linear counterparts, circular bacteriocins are highly stable over a broad temperature and pH range, and circularization decreases proteolytic degradation by exopeptidases. These features render them great potential as scaffold candidates to withstand strident conditions in food- and pharmaceutical applications. However, the biosynthesis and bioactivity of circular bacteriocins still remain largely unknown. To investigate and gain more insights into the biosynthesis of circular bacteriocins and to achieve efficient production and characterization of bacteriocin variants, we developed an efficient cloning and heterologous expression system for clostridial circularin A and successfully produced this circular peptide in Lactococcus lactis NZ9000. We report three system formats with single plasmid or plasmid combinations to achieve successful cloning and functional production of circularin A in L. lactis. These systematic varieties enabled us to choose the appropriate method to efficiently obtain various constructs with desired properties. With the established heterologous systems in L. lactis, we performed several mutagenesis studies in the precursor peptide to study its structure/function relationships. The overlay activity assay revealed that these mutant variants had variable effects on different indicator strains: lysine substitution for certain glutamine residue(s) greatly decreased its bioactivity against Clostridium perfringens and L. lactis NZ9000, and alanine replacement for the cationic residues significantly reduced the activity against Lactobacillus sake ATCC 15521, whereas alanine substitution for the aromatic residues decreased its bioactivity against all three testing strains dramatically. Moreover, the conditions for bacteriocin production were optimized. Results show that supplementing the minimal medium with extra glucose (or sucrose) and immediate nisin-induction improved the peptide yield significantly. Briefly, we developed an excellent system for the production of circularin A and a wide range of variant peptides in a convenient host, as well as a method for fast detection of peptide production and activity. This system facilitated our mutagenesis studies which provided valuable insights into the effects of mutating specific residues on its biosynthesis and bioactivity, and will eventually enable more complex research into the biosynthesis of circularin A.
Collapse
|
5
|
Biosynthesis and Production of Class II Bacteriocins of Food-Associated Lactic Acid Bacteria. FERMENTATION 2022. [DOI: 10.3390/fermentation8050217] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Bacteriocins are ribosomally synthesized peptides made by bacteria that inhibit the growth of similar or closely related bacterial strains. Class II bacteriocins are a class of bacteriocins that are heat-resistant and do not undergo extensive posttranslational modification. In lactic acid bacteria (LAB), class II bacteriocins are widely distributed, and some of them have been successfully applied as food preservatives or antibiotic alternatives. Class II bacteriocins can be further divided into four subcategories. In the same subcategory, variations were observed in terms of amino acid identity, peptide length, pI, etc. The production of class II bacteriocin is controlled by a dedicated gene cluster located in the plasmid or chromosome. Besides the pre-bacteriocin encoding gene, the gene cluster generally includes various combinations of immunity, transportation, and regulatory genes. Among class II bacteriocin-producing LAB, some strains/species showed low yield. A multitude of fermentation factors including medium composition, temperature, and pH have a strong influence on bacteriocin production which is usually strain-specific. Consequently, scientists are motivated to develop high-yielding strains through the genetic engineering approach. Thus, this review aims to present and discuss the distribution, sequence characteristics, as well as biosynthesis of class II bacteriocins of LAB. Moreover, the integration of modern biotechnology and genetics with conventional fermentation technology to improve bacteriocin production will also be discussed in this review.
Collapse
|
6
|
Giesler RJ, Spaltenstein P, Jacobsen MT, Xu W, Maqueda M, Kay MS. A glutamic acid-based traceless linker to address challenging chemical protein syntheses. Org Biomol Chem 2021; 19:8821-8829. [PMID: 34585207 PMCID: PMC8604549 DOI: 10.1039/d1ob01611c] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Native chemical ligation (NCL) enables the total chemical synthesis of proteins. However, poor peptide segment solubility remains a frequently encountered challenge. Here we introduce a traceless linker that can be temporarily attached to Glu side chains to overcome this problem. This strategy employs a new tool, Fmoc-Glu(AlHx)-OH, which can be directly installed using standard Fmoc-based solid-phase peptide synthesis. The incorporated residue, Glu(AlHx), is stable to a wide range of chemical protein synthesis conditions and is removed through palladium-catalyzed transfer under aqueous conditions. General handling characteristics, such as efficient incorporation, stability and rapid removal were demonstrated through a model peptide modified with Glu(AlHx) and a Lys6 solubilizing tag. Glu(AlHx) was incorporated into a highly insoluble peptide segment during the total synthesis of the bacteriocin AS-48. This challenging peptide was successfully synthesized and folded, and it has comparable antimicrobial activity to the native AS-48. We anticipate widespread use of this easy-to-use, robust linker for the preparation of challenging synthetic peptides and proteins.
Collapse
Affiliation(s)
- Riley J Giesler
- Department of Biochemistry, University of Utah School of Medicine, 15 North Medical Drive East, Room 4100, Salt Lake City, Utah 84112-5650, USA.
| | - Paul Spaltenstein
- Department of Biochemistry, University of Utah School of Medicine, 15 North Medical Drive East, Room 4100, Salt Lake City, Utah 84112-5650, USA.
| | - Michael T Jacobsen
- Department of Pediatrics, Division of Diabetes and Endocrinology, Stanford University, Palo Alto, CA 94304, USA
| | - Weiliang Xu
- Department of Biochemistry, University of Utah School of Medicine, 15 North Medical Drive East, Room 4100, Salt Lake City, Utah 84112-5650, USA.
| | - Mercedes Maqueda
- Departamento de Microbiología, Universidad de Granada, Avda. Fuentenueva, s/n, 18071 Granada, Spain
| | - Michael S Kay
- Department of Biochemistry, University of Utah School of Medicine, 15 North Medical Drive East, Room 4100, Salt Lake City, Utah 84112-5650, USA.
| |
Collapse
|
7
|
Crystal structure and site-directed mutagenesis of circular bacteriocin plantacyclin B21AG reveals cationic and aromatic residues important for antimicrobial activity. Sci Rep 2020; 10:17398. [PMID: 33060678 PMCID: PMC7562740 DOI: 10.1038/s41598-020-74332-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 09/21/2020] [Indexed: 12/02/2022] Open
Abstract
Plantacyclin B21AG is a circular bacteriocin produced by Lactiplantibacillus plantarum B21 which displays antimicrobial activity against various Gram-positive bacteria including foodborne pathogens, Listeria monocytogenes and Clostridium perfringens. It is a 58-amino acid cyclised antimicrobial peptide, with the N and C termini covalently linked together. The circular peptide backbone contributes to remarkable stability, conferring partial proteolytic resistance and structural integrity under a wide temperature and pH range. Here, we report the first crystal structure of a circular bacteriocin from a food grade Lactobacillus. The protein was crystallised using the hanging drop vapour diffusion method and the structure solved to a resolution of 1.8 Å. Sequence alignment against 18 previously characterised circular bacteriocins revealed the presence of conserved charged and aromatic residues. Alanine substitution mutagenesis validated the importance of these residues. Minimum inhibitory concentration analysis of these Ala mutants showed that Phe8Ala and Trp45Ala mutants displayed a 48- and 32-fold reduction in activity, compared to wild type. The Lys19Ala mutant displayed the weakest activity, with a 128-fold reduction. These experiments demonstrate the relative importance of aromatic and cationic residues for the antimicrobial activity of plantacyclin B21AG and by extension, other circular bacteriocins sharing these evolutionarily conserved residues.
Collapse
|
8
|
Al-Madboly LA, El-Deeb NM, Kabbash A, Nael MA, Kenawy AM, Ragab AE. Purification, Characterization, Identification, and Anticancer Activity of a Circular Bacteriocin From Enterococcus thailandicus. Front Bioeng Biotechnol 2020; 8:450. [PMID: 32656185 PMCID: PMC7324803 DOI: 10.3389/fbioe.2020.00450] [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: 02/02/2020] [Accepted: 04/20/2020] [Indexed: 11/13/2022] Open
Abstract
New anticancer agents are continually needed because cancerous cells continue to evolve resistance to the currently available chemotherapeutic agents. The aim of the present study was to screen, purify and characterize a hepatotoxic bacteriocin from Enterococcus species. The production of bacteriocin from the Enterococcus isolates was achieved based on their antibacterial activity against indicator reference strains. Enterococcus isolates showed a broad spectrum of antibacterial activity by forming inhibition zones with diameters ranged between 12 and 29 mm. The most potent bacteriocin producing strain was molecularly identified as Enterococcus thailandicus. The crude extracted bacteriocin was purified by cation exchange and size exclusion chromatography that resulted in 83 fractions. Among them, 18 factions were considered as bacteriocins based on their positive antibacterial effects. The anticancer effects of the purified bacteriocins were tested against HepG2 cell line. The most promising enterocin (LNS18) showed the highest anticancer effects against HepG2 cells (with 75.24% cellular inhibition percentages), with IC50 value 15.643 μM and without any significant cytotoxic effects on normal fibroblast cells (BJ ATCC® CRL-2522™). The mode of anticancer action of enterocin LNS18 against HepG2 cells could be explained by its efficacy to induce cellular ROS, decrease HepG2 CD markers and arrest cells in G0 phase. Amino acid sequence of enterocin LNS18 was determined and the deduced peptide of the structural gene showed 86 amino acids that shared 94.7% identity with enterocin NKR-5-3B from E. faecium. Enterocin LNS18 consisted of 6 α-helices; 5 circular and one linear. Model-template alignment constructed between enterocin LNS18 and NKR-5-3B revealed 95.31% identity. The predicted 3D homology model of LNS18, after circularization and release of 22 amino acids, showed the formation of a bond between Leu23 and Trp86 amino acid residues at the site of circularization. Furthermore, areas of positive charges were due to the presence of 6 lysine residues resulting in a net positive charge of +4 on the bacteriocin surface. Based on the above mentioned results, our characterized bacteriocin is a promising agent to target liver cancer without any significant toxic effects on normal cell lines.
Collapse
Affiliation(s)
- Lamiaa A Al-Madboly
- Department of Pharmaceutical Microbiology, Faculty of Pharmacy, Tanta University, Tanta, Egypt
| | - Nehal M El-Deeb
- Biopharmaceutical Products Research Department, Genetic Engineering and Biotechnology Research Institute, City of Scientific Research and Technological Applications (SRTA-City), Alexandria, Egypt
| | - Amal Kabbash
- Department of Pharmacognosy, Faculty of Pharmacy, Tanta University, Tanta, Egypt
| | - Manal A Nael
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Tanta University, Tanta, Egypt
| | - Ahmed M Kenawy
- Nucleic Acids Research Department, Genetic Engineering and Biotechnology Research Institute, City of Scientific Research and Technological Applications (SRTA-City), Alexandria, Egypt
| | - Amany E Ragab
- Department of Pharmacognosy, Faculty of Pharmacy, Tanta University, Tanta, Egypt
| |
Collapse
|
9
|
Vezina B, Rehm BHA, Smith AT. Bioinformatic prospecting and phylogenetic analysis reveals 94 undescribed circular bacteriocins and key motifs. BMC Microbiol 2020; 20:77. [PMID: 32252629 PMCID: PMC7132975 DOI: 10.1186/s12866-020-01772-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Accepted: 03/29/2020] [Indexed: 12/19/2022] Open
Abstract
Background Circular bacteriocins are antimicrobial peptides produced by bacteria with a N and C termini ligation. They have desirable properties such as activity at low concentrations along with thermal, pH and proteolytic resistance. There are twenty experimentally confirmed circular bacteriocins as part of bacteriocin gene clusters, with transport, membrane and immunity proteins. Traditionally, novel antimicrobials are found by testing large numbers of isolates against indicator strains, with no promise of corresponding novel sequence. Results Through bioprospecting publicly available sequence databases, we identified ninety-nine circular bacteriocins across a variety of bacteria bringing the total to 119. They were grouped into two families within class I modified bacteriocins (i and ii) and further divided into subfamilies based on similarity to experimentally confirmed circular bacteriocins. Within subfamilies, sequences overwhelmingly shared similar characteristics such as sequence length, presence of a polybasic region, conserved locations of aromatic residues, C and N termini, gene clusters similarity, translational coupling and hydrophobicity profiles. At least ninety were predicted to be putatively functional based on gene clusters. Furthermore, bacteriocins identified from Enterococcus, Staphylococcus and Streptococcus species may have activity against clinically relevant strains, due to the presence of putative immunity genes required for expression in a toxin-antitoxin system. Some strains such as Paenibacillus larvae subsp. pulvifaciens SAG 10367 contained multiple circular bacteriocin gene clusters from different subfamilies, while some strains such as Bacillus cereus BCE-01 contained clusters with multiple circular bacteriocin structural genes. Conclusions Sequence analysis provided rapid insight into identification of novel, putative circular bacteriocins, as well as conserved genes likely essential for circularisation. This represents an expanded library of putative antimicrobial proteins which are potentially active against human, plant and animal pathogens.
Collapse
Affiliation(s)
- Ben Vezina
- Centre for Cell Factories and Biopolymers, Griffith Institute for Drug Discovery, Griffith University, Nathan, Australia
| | - Bernd H A Rehm
- Centre for Cell Factories and Biopolymers, Griffith Institute for Drug Discovery, Griffith University, Nathan, Australia
| | - Andrew T Smith
- Centre for Cell Factories and Biopolymers, Griffith Institute for Drug Discovery, Griffith University, Nathan, Australia.
| |
Collapse
|
10
|
Abdel Monaim SAH, Somboro AM, El-Faham A, de la Torre BG, Albericio F. Bacteria Hunt Bacteria through an Intriguing Cyclic Peptide. ChemMedChem 2018; 14:24-51. [PMID: 30394699 DOI: 10.1002/cmdc.201800597] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 10/10/2018] [Indexed: 12/15/2022]
Abstract
In the last few decades, peptides have been victorious over small molecules as therapeutics due to their broad range of applications, high biological activity, and high specificity. However, the main challenges to overcome if peptides are to become effective drugs is their low oral bioavailability and instability under physiological conditions. Cyclic peptides play a vital role in this context because they show higher stability under physiological conditions, higher membrane permeability, and greater oral bioavailability than that of their corresponding linear analogues. In this regard, cyclic antimicrobial peptides (AMPs) have gained considerable attention in the field of novel antibiotic development. Bacterial strains produce cyclic AMPs through two pathways: ribosomal and nonribosomal. This review provides an overview of the chemical classification of cyclic AMPs isolated from bacteria, and provides a description of their biological activity and mode of action.
Collapse
Affiliation(s)
- Shimaa A H Abdel Monaim
- KwaZulu-Natal Research Innovation and Sequencing Platform (KRISP), School of Laboratory Medicine and Medical Sciences, College of Health Sciences, University of KwaZulu-Natal, Durban, 4041, South Africa.,Peptide Science Laboratory, School of Chemistry and Physics, University of KwaZulu-Natal, Durban, 4001, South Africa
| | - Anou M Somboro
- Biomedical Resource Unit, School of Laboratory Medicine and Medical Sciences, College of Health Sciences, University of KwaZulu-Natal, Durban, 4041, South Africa
| | - Ayman El-Faham
- Department of Chemistry, College of Science, King Saud University, P.O. Box 2455, Riyadh, 11451, Saudi Arabia.,Chemistry Department, Faculty of Science, Alexandria University, P.O. Box 426, Ibrahimia, Alexandria, 12321, Egypt
| | - Beatriz G de la Torre
- KwaZulu-Natal Research Innovation and Sequencing Platform (KRISP), School of Laboratory Medicine and Medical Sciences, College of Health Sciences, University of KwaZulu-Natal, Durban, 4041, South Africa
| | - Fernando Albericio
- Peptide Science Laboratory, School of Chemistry and Physics, University of KwaZulu-Natal, Durban, 4001, South Africa.,Department of Chemistry, College of Science, King Saud University, P.O. Box 2455, Riyadh, 11451, Saudi Arabia.,CIBER-BBN, Networking Centre on Bioengineering, Biomaterials and Nanomedicine, and Department of Organic Chemistry, University of Barcelona, Barcelona, 08028, Spain
| |
Collapse
|
11
|
Perez RH, Zendo T, Sonomoto K. Circular and Leaderless Bacteriocins: Biosynthesis, Mode of Action, Applications, and Prospects. Front Microbiol 2018; 9:2085. [PMID: 30233551 PMCID: PMC6131525 DOI: 10.3389/fmicb.2018.02085] [Citation(s) in RCA: 103] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 08/15/2018] [Indexed: 01/02/2023] Open
Abstract
Bacteriocins are a huge family of ribosomally synthesized peptides known to exhibit a range of bioactivities, most predominantly antibacterial activities. Bacteriocins from lactic acid bacteria are of particular interest due to the latter's association to food fermentation and the general notion of them to be safe. Among the family of bacteriocins, the groups known as circular bacteriocins and leaderless bacteriocins are gaining more attention due to their enormous potential for industrial application. Circular bacteriocins and leaderless bacteriocins, arguably the least understood groups of bacteriocins, possess distinctively peculiar characteristics in their structures and biosynthetic mechanisms. Circular bacteriocins have N-to-C- terminal covalent linkage forming a structurally distinct circular peptide backbone. The circular nature of their structures provides them superior stability against various stresses compared to most linear bacteriocins. The molecular mechanism of their biosynthesis, albeit has remained poorly understood, is believed to possesses huge application prospect as it can serve as scaffold in bioengineering other biologically important peptides. On the other hand, while most bacteriocins are synthesized as inactive precursor peptides, which possess an N-terminal leader peptide attached to a C-terminal propeptide, leaderless bacteriocins are atypical as they do not have an N-terminal leader peptide, hence the name. Leaderless bacteriocins are active right after translation as they do not undergo any post-translational processing common to other groups of bacteriocins. This "simplicity" in the biosynthesis of leaderless bacteriocins offers a huge commercial potential as scale-up production systems are considerably easier to assemble. In this review, we summarize the current studies of both circular and leaderless bacteriocins, highlighting the progress in understanding their biosynthesis, mode of action, application and their prospects.
Collapse
Affiliation(s)
- Rodney H Perez
- Department of Bioscience and Biotechnology, Faculty of Agriculture, Graduate School, Kyushu University, Fukuoka, Japan.,National Institute of Molecular Biology and Biotechnology, University of the Philippines Los Baños, Los Baños, Philippines
| | - Takeshi Zendo
- Department of Bioscience and Biotechnology, Faculty of Agriculture, Graduate School, Kyushu University, Fukuoka, Japan
| | - Kenji Sonomoto
- Department of Bioscience and Biotechnology, Faculty of Agriculture, Graduate School, Kyushu University, Fukuoka, Japan
| |
Collapse
|
12
|
van Heel AJ, Montalban-Lopez M, Oliveau Q, Kuipers OP. Genome-guided identification of novel head-to-tail cyclized antimicrobial peptides, exemplified by the discovery of pumilarin. Microb Genom 2017; 3:e000134. [PMID: 29177092 PMCID: PMC5695211 DOI: 10.1099/mgen.0.000134] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2017] [Accepted: 09/01/2017] [Indexed: 11/18/2022] Open
Abstract
The need for novel antibiotics in an era where antimicrobial resistance is on the rise, and the number of new approved antimicrobial drugs reaching the market is declining, is evident. The underused potential of post-translationally modified peptides for clinical use makes this class of peptides interesting candidates. In this study, we made use of the vast amounts of available genomic data and screened all publicly available prokaryotic genomes (~3000) to identify 394 novel head-to-tail cyclized antimicrobial peptides. To verify these in silico results, we isolated and characterized a novel antimicrobial peptide from Bacillus pumilus that we named pumilarin. Pumilarin was demonstrated to have a circular structure and showed antimicrobial activity against several indicator strains, including pathogens.
Collapse
Affiliation(s)
- Auke J van Heel
- 1Molecular Genetics, University of Groningen, Groningen, Nijenborgh 7, NA 9747 AG, The Netherlands
| | - Manuel Montalban-Lopez
- 1Molecular Genetics, University of Groningen, Groningen, Nijenborgh 7, NA 9747 AG, The Netherlands.,2Department of Microbiology, University of Granada, Granada, Spain
| | - Quentin Oliveau
- 1Molecular Genetics, University of Groningen, Groningen, Nijenborgh 7, NA 9747 AG, The Netherlands
| | - Oscar P Kuipers
- 1Molecular Genetics, University of Groningen, Groningen, Nijenborgh 7, NA 9747 AG, The Netherlands
| |
Collapse
|
13
|
Rohrbacher F, Zwicky A, Bode JW. Chemical synthesis of a homoserine-mutant of the antibacterial, head-to-tail cyclized protein AS-48 by α-ketoacid-hydroxylamine (KAHA) ligation. Chem Sci 2017; 8:4051-4055. [PMID: 28580120 PMCID: PMC5434751 DOI: 10.1039/c7sc00789b] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2017] [Accepted: 03/23/2017] [Indexed: 12/15/2022] Open
Abstract
An antibacterial cyclic AS-48 protein was chemically synthesized by α-ketoacid-hydroxylamine (KAHA) ligation. Initial challenges associated with the exceptionally hydrophobic segments arising from the amphiphilic nature of the protein were resolved by the development of bespoke reaction conditions for hydrophobic segments, using hexafluoroisopropanol (HFIP) as a co-solvent. The synthetic protein displays similar biological activity and properties to those of the native protein. To support the current understanding of its antibacterial mode of action, we demonstrate the ability of AS-48 to be incorporated into synthetic multilamellar vesicles (MLVs).
Collapse
Affiliation(s)
- Florian Rohrbacher
- Laboratorium für Organische Chemie , Department of Chemistry and Applied Biosciences , ETH Zürich , 8093 Zürich , Switzerland .
| | - André Zwicky
- Laboratorium für Organische Chemie , Department of Chemistry and Applied Biosciences , ETH Zürich , 8093 Zürich , Switzerland .
| | - Jeffrey W Bode
- Laboratorium für Organische Chemie , Department of Chemistry and Applied Biosciences , ETH Zürich , 8093 Zürich , Switzerland . .,Institute of Transformative bio-Molecules (WPI-ITbM) , Nagoya University , Chikusa , Nagoya 464-8602 , Japan
| |
Collapse
|
14
|
Perez RH, Sugino H, Ishibashi N, Zendo T, Wilaipun P, Leelawatcharamas V, Nakayama J, Sonomoto K. Mutations near the cleavage site of enterocin NKR-5-3B prepeptide reveal new insights into its biosynthesis. Microbiology (Reading) 2017; 163:431-441. [DOI: 10.1099/mic.0.000435] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Rodney H Perez
- Laboratory of Microbial Technology, Division of Systems Bioengineering, Department of Bioscience and Biotechnology, Faculty of Agriculture, Graduate School, Kyushu University, Fukuoka 812-8581, Japan
- Present address: National Institute for Molecular Biology and Biotechnology (BIOTECH), University of the Philippines Los Baños, Laguna 4031, Philippines
| | - Haruki Sugino
- Laboratory of Microbial Technology, Division of Systems Bioengineering, Department of Bioscience and Biotechnology, Faculty of Agriculture, Graduate School, Kyushu University, Fukuoka 812-8581, Japan
| | - Naoki Ishibashi
- Laboratory of Microbial Technology, Division of Systems Bioengineering, Department of Bioscience and Biotechnology, Faculty of Agriculture, Graduate School, Kyushu University, Fukuoka 812-8581, Japan
| | - Takeshi Zendo
- Laboratory of Microbial Technology, Division of Systems Bioengineering, Department of Bioscience and Biotechnology, Faculty of Agriculture, Graduate School, Kyushu University, Fukuoka 812-8581, Japan
| | - Pongtep Wilaipun
- Department of Fishery Products, Faculty of Fisheries, Kasetsart University, Chatuchak, Bangkok, Thailand
| | - Vichien Leelawatcharamas
- Department of Biotechnology, Faculty of Agro-Industry, Kasetsart University, Chatuchak, Bangkok 10900, Thailand
| | - Jiro Nakayama
- Laboratory of Microbial Technology, Division of Systems Bioengineering, Department of Bioscience and Biotechnology, Faculty of Agriculture, Graduate School, Kyushu University, Fukuoka 812-8581, Japan
| | - Kenji Sonomoto
- Laboratory of Microbial Technology, Division of Systems Bioengineering, Department of Bioscience and Biotechnology, Faculty of Agriculture, Graduate School, Kyushu University, Fukuoka 812-8581, Japan
- Laboratory of Functional Food Design, Department of Functional Metabolic Design, Bio-Architecture Center, Kyushu University, Fukuoka 812-8581, Japan
| |
Collapse
|
15
|
Truman AW. Cyclisation mechanisms in the biosynthesis of ribosomally synthesised and post-translationally modified peptides. Beilstein J Org Chem 2016; 12:1250-68. [PMID: 27559376 PMCID: PMC4979651 DOI: 10.3762/bjoc.12.120] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Accepted: 06/02/2016] [Indexed: 12/15/2022] Open
Abstract
Ribosomally synthesised and post-translationally modified peptides (RiPPs) are a large class of natural products that are remarkably chemically diverse given an intrinsic requirement to be assembled from proteinogenic amino acids. The vast chemical space occupied by RiPPs means that they possess a wide variety of biological activities, and the class includes antibiotics, co-factors, signalling molecules, anticancer and anti-HIV compounds, and toxins. A considerable amount of RiPP chemical diversity is generated from cyclisation reactions, and the current mechanistic understanding of these reactions will be discussed here. These cyclisations involve a diverse array of chemical reactions, including 1,4-nucleophilic additions, [4 + 2] cycloadditions, ATP-dependent heterocyclisation to form thiazolines or oxazolines, and radical-mediated reactions between unactivated carbons. Future prospects for RiPP pathway discovery and characterisation will also be highlighted.
Collapse
Affiliation(s)
- Andrew W Truman
- Department of Molecular Microbiology, John Innes Centre, Colney Lane, Norwich, NR4 7UH, UK
| |
Collapse
|
16
|
Circular bacteriocins: biosynthesis and mode of action. Appl Environ Microbiol 2014; 80:6854-62. [PMID: 25172850 DOI: 10.1128/aem.02284-14] [Citation(s) in RCA: 94] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Circular bacteriocins are a group of N-to-C-terminally linked antimicrobial peptides, produced by Gram-positive bacteria of the phylum Firmicutes. Circular bacteriocins generally exhibit broad-spectrum antimicrobial activity, including against common food-borne pathogens, such as Clostridium and Listeria spp. These peptides are further known for their high pH and thermal stability, as well as for resistance to many proteolytic enzymes, properties which make this group of bacteriocins highly promising for potential industrial applications and their biosynthesis of particular interest as a possible model system for the synthesis of highly stable bioactive peptides. In this review, we summarize the current knowledge on this group of bacteriocins, with emphasis on the recent progress in understanding circular bacteriocin genetics, biosynthesis, and mode of action; in addition, we highlight the current challenges and future perspectives for the application of these peptides.
Collapse
|
17
|
Cebrián R, Rodríguez-Ruano S, Martínez-Bueno M, Valdivia E, Maqueda M, Montalbán-López M. Analysis of the promoters involved in enterocin AS-48 expression. PLoS One 2014; 9:e90603. [PMID: 24594763 PMCID: PMC3942455 DOI: 10.1371/journal.pone.0090603] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2013] [Accepted: 01/31/2014] [Indexed: 11/17/2022] Open
Abstract
The enterocin AS-48 is the best characterized antibacterial circular protein in prokaryotes. It is a hydrophobic and cationic bacteriocin, which is ribosomally synthesized by enterococcal cells and post-translationally cyclized by a head-to-tail peptide bond. The production of and immunity towards AS-48 depend upon the coordinated expression of ten genes organized in two operons, as-48ABC (where genes encoding enzymes with processing, secretion, and immunity functions are adjacent to the structural as-48A gene) and as-48C1DD1EFGH. The current study describes the identification of the promoters involved in AS-48 expression. Seven putative promoters have been here amplified, and separately inserted into the promoter-probe vector pTLR1, to create transcriptional fusions with the mCherry gene used as a reporter. The activity of these promoter regions was assessed measuring the expression of the fluorescent mCherry protein using the constitutive pneumococcal promoter PX as a reference. Our results revealed that only three promoters PA, P2(2) and PD1 were recognized in Enterococcus faecalis, Lactococcus lactis and Escherichia coli, in the conditions tested. The maximal fluorescence was obtained with PX in all the strains, followed by the P2(2) promoter, which level of fluorescence was 2-fold compared to PA and 4-fold compared to PD1. Analysis of putative factors influencing the promoter activity in single and double transformants in E. faecalis JH2-2 demonstrated that, in general, a better expression was achieved in presence of pAM401-81. In addition, the P2(2) promoter could be regulated in a negative fashion by genes existing in the native pMB-2 plasmid other than those of the as-48 cluster, while the pH seems to affect differently the as-48 promoter expression.
Collapse
Affiliation(s)
- Rubén Cebrián
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Granada, Granada, Spain
| | - Sonia Rodríguez-Ruano
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Granada, Granada, Spain
| | - Manuel Martínez-Bueno
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Granada, Granada, Spain
| | - Eva Valdivia
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Granada, Granada, Spain
| | - Mercedes Maqueda
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Granada, Granada, Spain
| | - Manuel Montalbán-López
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Granada, Granada, Spain
| |
Collapse
|
18
|
Functional genetic analysis of the GarML gene cluster in Lactococcus garvieae DCC43 gives new insights into circular bacteriocin biosynthesis. J Bacteriol 2013; 196:911-9. [PMID: 24336941 DOI: 10.1128/jb.01115-13] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Garvicin ML (GarML) is a circular bacteriocin produced by Lactococcus garvieae DCC43. The recently published draft genome of this strain allowed determination of the genetic background for bacteriocin production. Bioinformatic analysis identified a gene cluster consisting of nine open reading frames likely involved in the production of and immunity to GarML. The garA gene encodes the bacteriocin precursor, garX a large transmembrane protein, garBCDE a putative immunity protein (garB) followed by an ATPase and two transmembrane proteins, and garFGH a putative ABC transporter complex. Functional genetic analysis revealed that deletion of garFGH had no effect on sensitivity to or production of GarML. In contrast, deletion of garBCDE or inactivation of garX resulted in high-level sensitivity to GarML and completely abolished production of active bacteriocin. Mass spectrometry of culture supernatants revealed that wild-type cultures contained the mature circular form as well as the linear forms of the bacteriocin, both with and without the three-amino-acid leader sequence, while bacteriocin-negative mutants contained only the linear forms. These results indicate that cleavage of the leader peptide precedes circularization and is likely performed by a functional entity separate from the GarML gene cluster. To our knowledge, this is the first conclusive evidence for these processes being separated in time. Loss of immunity and antimicrobial activity in addition to our inability to detect the circular bacteriocin in the ΔgarBCDE and garX::pCG47 mutants demonstrate that both these units are indispensable for GarML biosynthesis as well as immunity. Furthermore, the results indicate that these genes are implicated in the circularization of the bacteriocin and that their functions are probably interlinked.
Collapse
|
19
|
Arnison PG, Bibb MJ, Bierbaum G, Bowers AA, Bugni TS, Bulaj G, Camarero JA, Campopiano DJ, Challis GL, Clardy J, Cotter PD, Craik DJ, Dawson M, Dittmann E, Donadio S, Dorrestein PC, Entian KD, Fischbach MA, Garavelli JS, Göransson U, Gruber CW, Haft DH, Hemscheidt TK, Hertweck C, Hill C, Horswill AR, Jaspars M, Kelly WL, Klinman JP, Kuipers OP, Link AJ, Liu W, Marahiel MA, Mitchell DA, Moll GN, Moore BS, Müller R, Nair SK, Nes IF, Norris GE, Olivera BM, Onaka H, Patchett ML, Piel J, Reaney MJT, Rebuffat S, Ross RP, Sahl HG, Schmidt EW, Selsted ME, Severinov K, Shen B, Sivonen K, Smith L, Stein T, Süssmuth RD, Tagg JR, Tang GL, Truman AW, Vederas JC, Walsh CT, Walton JD, Wenzel SC, Willey JM, van der Donk WA. Ribosomally synthesized and post-translationally modified peptide natural products: overview and recommendations for a universal nomenclature. Nat Prod Rep 2013; 30:108-60. [PMID: 23165928 DOI: 10.1039/c2np20085f] [Citation(s) in RCA: 1470] [Impact Index Per Article: 133.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
This review presents recommended nomenclature for the biosynthesis of ribosomally synthesized and post-translationally modified peptides (RiPPs), a rapidly growing class of natural products. The current knowledge regarding the biosynthesis of the >20 distinct compound classes is also reviewed, and commonalities are discussed.
Collapse
Affiliation(s)
- Paul G Arnison
- Prairie Plant Systems Inc, Botanical Alternatives Inc, Suite 176, 8B-3110 8th Street E, Saskatoon, SK, S7H 0W2, Canada
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
20
|
Montalbán-López M, Sánchez-Hidalgo M, Cebrián R, Maqueda M. Discovering the bacterial circular proteins: bacteriocins, cyanobactins, and pilins. J Biol Chem 2012; 287:27007-13. [PMID: 22700986 DOI: 10.1074/jbc.r112.354688] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Over recent years, several examples of natural ribosomally synthesized circular proteins and peptides from diverse organisms have been described. They are a group of proteins for which the precursors must be post-translationally modified to join the N and C termini with a peptide bond. This feature appears to confer a range of potential advantages because these proteins show increased resistance to proteases and higher thermodynamic stability, both of which improve their biological activity. They are produced by prokaryotic and eukaryotic organisms and show diverse biological activities, related mostly to a self-defense or competition mechanism of the producer organisms, with the only exception being the circular pilins. This minireview highlights ribosomally synthesized circular proteins produced by members of the domain Bacteria: circular bacteriocins, cyanobactins, and circular pilins. We pay special attention to the genetic organization of the biosynthetic machinery of these molecules, the role of circularization, and the differences in the possible circularization mechanisms.
Collapse
Affiliation(s)
- Manuel Montalbán-López
- Department of Molecular Genetics, University of Groningen, 9747 AG Groningen, The Netherlands
| | | | | | | |
Collapse
|
21
|
DU LIHUI, SOMKUTI GEORGEA, RENYE JR JOHNA, HUO GUICHENG. PROPERTIES OF DURANCIN GL, A NEW ANTILISTERIAL BACTERIOCIN PRODUCED BY ENTEROCOCCUS DURANS 41D. J Food Saf 2011. [DOI: 10.1111/j.1745-4565.2011.00346.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
22
|
Identification and characterization of leucocyclicin Q, a novel cyclic bacteriocin produced by Leuconostoc mesenteroides TK41401. Appl Environ Microbiol 2011; 77:8164-70. [PMID: 21948835 DOI: 10.1128/aem.06348-11] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The culture supernatant of Leuconostoc mesenteroides TK41401, isolated from Japanese pickles, possessed antimicrobial activity against broad range of a bacterial genera and particularly strong activity against Bacillus coagulans, the major contaminant of pickles. An antimicrobial peptide was purified in three chromatographic steps, and its molecular mass was determined to be 6,115.59 Da by electrospray ionization time-of-flight mass spectrometry (ESI-TOF MS). The primary structure of this peptide was determined by amino acid and DNA sequencing, and these analyses revealed that it was translated as a 63-residue precursor. This precursor showed high similarity to the precursor of lactocyclicin Q, a cyclic bacteriocin produced by Lactococcus sp. strain QU 12. The molecular weight calculated after cyclization, which was presumed to involve the same process as in lactocyclicin Q (between L3 and W63), agreed with that estimated by ESI-TOF MS. This peptide was proved to be a novel cyclic bacteriocin, and it was termed leucocyclicin Q. The antimicrobial spectrum of this bacteriocin clearly differed from that of lactocyclicin Q, even though their primary structures were quite similar. This is the first report of a cyclic bacteriocin produced by a strain of the genus Leuconostoc.
Collapse
|
23
|
Sánchez-Hidalgo M, Montalbán-López M, Cebrián R, Valdivia E, Martínez-Bueno M, Maqueda M. AS-48 bacteriocin: close to perfection. Cell Mol Life Sci 2011; 68:2845-57. [PMID: 21590312 PMCID: PMC11115006 DOI: 10.1007/s00018-011-0724-4] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2011] [Revised: 04/06/2011] [Accepted: 05/03/2011] [Indexed: 10/18/2022]
Abstract
Bacteriocin AS-48 is an intriguing molecule because of its unique structural characteristics, genetic regulation, broad activity spectrum, and potential biotechnological applications. It was the first reported circular bacteriocin and has been undoubtedly the best characterized for the last 25 years. Thus, AS-48 is the prototype of circular bacteriocins (class IV), for which the structure and genetic regulation have been elucidated. This review discusses the state-of-the-art in genetic engineering with regard to this circular protein, with the use of site-directed mutagenesis and circular permutation. Mutagenesis studies have been used to unravel the role of (a) different residues in the biological activity, underlining the relevance of several residues involved in membrane interaction and the low correlation between stability and activity and (b) three amino acids involved in maturation, providing information on the specificity of the leader peptidase and the circularization process itself. To investigate the role of circularity in the stability and biological properties of the enterocin AS-48, two different ways of linearization have been attempted: in vitro by limited proteolysis experiments and in vivo by circular permutation in the structural gene as-48A. The results summarized here show the significance of circularization on the secondary structure, potency and, especially, the stability of AS-48 and point as well to a putative role of the leader peptide as a protecting moiety in the pre-proprotein. Taken all together, the data available on circular bacteriocins support the idea that AS-48 has been engineered by nature to make a remarkably active and stable protein with a broad spectrum of activity.
Collapse
Affiliation(s)
| | - Manuel Montalbán-López
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Granada, Fuentenueva s/n, 18071 Granada, Spain
| | - Rubén Cebrián
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Granada, Fuentenueva s/n, 18071 Granada, Spain
| | - Eva Valdivia
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Granada, Fuentenueva s/n, 18071 Granada, Spain
| | - Manuel Martínez-Bueno
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Granada, Fuentenueva s/n, 18071 Granada, Spain
| | - Mercedes Maqueda
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Granada, Fuentenueva s/n, 18071 Granada, Spain
| |
Collapse
|
24
|
van Belkum MJ, Martin-Visscher LA, Vederas JC. Structure and genetics of circular bacteriocins. Trends Microbiol 2011; 19:411-8. [PMID: 21664137 DOI: 10.1016/j.tim.2011.04.004] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2011] [Revised: 04/14/2011] [Accepted: 04/29/2011] [Indexed: 10/18/2022]
Abstract
Circular bacteriocins are antimicrobial peptides produced by a variety of Gram-positive bacteria. They are part of a growing family of ribosomally synthesized peptides with a head-to-tail cyclization of their backbone that are found in mammals, plants, fungi and bacteria and are exceptionally stable. These bacteriocins permeabilize the membrane of sensitive bacteria, causing loss of ions and dissipation of the membrane potential. Most circular bacteriocins probably adopt a common 3D structure consisting of four or five α-helices encompassing a hydrophobic core. This review compares the various structures, as well as the gene clusters that encode circular bacteriocins, and discusses the biogenesis of this unique class of bacteriocins.
Collapse
|