Julien Tailhades
@research.monash.edu
Senior Research Fellow - Monash Biomedicine Discovery Institute
Monash University
RESEARCH, TEACHING, or OTHER INTERESTS
Chemistry, Biochemistry, Microbiology, Infectious Diseases
Scopus Publications
Scopus Publications
Mathias H. Hansen, Angus Keto, Maxine Treisman, Vishnu Mini Sasi, Laura Coe, Yongwei Zhao, Leo Padva, Caroline Hess, Victor Leichthammer, Daniel L. Machell,et al.
American Chemical Society (ACS)
Edward Marschall, Rachel W. Cass, Komal M. Prasad, James D. Swarbrick, Alasdair I. McKay, Jennifer A. E. Payne, Max J. Cryle, and Julien Tailhades
Royal Society of Chemistry (RSC)
Optimized solid-phase peptide synthesis (SPPS) conditions allow the incorporation of multiple arylglycine residues which is offering a new perspective on the peptide antibiotic ramoplanin.
Thomas N. G. Handley, Praveen Praveen, Julien Tailhades, Hongkang Wu, Ross A. D. Bathgate, and Mohammed Akhter Hossain
MDPI AG
Human relaxin-2 (H2 relaxin) is a peptide hormone with potent vasodilatory and anti-fibrotic effects, which is of interest for the treatment of heart failure and fibrosis. H2 relaxin binds to the Relaxin Family Peptide Receptor 1 (RXFP1). Native H2 relaxin is a two-chain, three-disulfide-bond-containing peptide, which is unstable in human serum and difficult to synthesize efficiently. In 2016, our group developed B7-33, a single-chain peptide derived from the B-chain of H2 relaxin. B7-33 demonstrated poor affinity and potency in HEK cells overexpressing RXFP1; however, it displayed equivalent potency to H2 relaxin in fibroblasts natively expressing RXFP1, where it also demonstrated the anti-fibrotic effects of the native hormone. B7-33 reversed organ fibrosis in numerous pre-clinical animal studies. Here, we detail our efforts towards a minimal H2 relaxin scaffold and attempts to improve scaffold activity through Aib substitution and hydrocarbon stapling to re-create the peptide helicity present in the native H2 relaxin.
Songya Zhang, Lin Zhang, Anja Greule, Julien Tailhades, Edward Marschall, Panward Prasongpholchai, Daniel J. Leng, Jingfan Zhang, Jing Zhu, Joe A. Kaczmarski,et al.
Elsevier BV
Y. T. Candace Ho, Joe A. Kaczmarski, Julien Tailhades, Thierry Izoré, David L. Steer, Ralf B. Schittenhelm, Manuela Tosin, Colin J. Jackson, and Max J. Cryle
Royal Society of Chemistry (RSC)
Chemical stabilisation of carrier protein bound substrates in non-ribosomal peptide synthesis can result in a loss in activity of neighbouring catalytic domains.
Y. T. Candace Ho, Ralf B. Schittenhelm, Dumitrita Iftime, Evi Stegmann, Julien Tailhades, and Max J. Cryle
Wiley
AbstractThe glycopeptide antibiotics (GPAs) are a clinically approved class of antimicrobial agents that classically function through the inhibition of bacterial cell‐wall biosynthesis by sequestration of the precursor lipid II. The oxidative crosslinking of the core peptide by cytochrome P450 (Oxy) enzymes during GPA biosynthesis is both essential to their function and the source of their synthetic challenge. Thus, understanding the activity and selectivity of these Oxy enzymes is of key importance for the future engineering of this important compound class. Recent reports of GPAs that display an alternative mode of action and a wider range of core peptide structures compared to classic lipid II‐binding GPAs raises the question of the tolerance of Oxy enzymes for larger changes in their peptide substrates. In this work, we explore the ability of Oxy enzymes from the biosynthesis pathways of lipid II‐binding GPAs to accept altered peptide substrates based on a vancomycin template. Our results show that Oxy enzymes are more tolerant of changes at the N terminus of their substrates, whilst C‐terminal extension of the peptide substrates is deleterious to the activity of all Oxy enzymes. Thus, future studies should prioritise the study of Oxy enzymes from atypical GPA biosynthesis pathways bearing C‐terminal peptide extension to increase the substrate scope of these important cyclisation enzymes.
Maxine Treisman, Laura Coe, Yongwei Zhao, Vishnu Mini Sasi, Jemma Gullick, Mathias H. Hansen, Aviva Ly, Victor Leichthammer, Caroline Hess, Daniel L. Machell,et al.
American Chemical Society (ACS)
Cytochrome-P450-mediated cross-linking of ribosomally encoded peptides (RiPPs) is rapidly expanding and displays great potential for biocatalysis. Here, we demonstrate that active site engineering of the biarylitide cross-linking enzyme P450Blt enables the formation of His-X-Tyr and Tyr-X-Tyr cross-linked peptides, thus showing how such P450s can be further exploited to produce alternate cyclic tripeptides with controlled cross-linking states.
Y. T. Candace Ho, Yongwei Zhao, Julien Tailhades, and Max J. Cryle
Springer US
Yongwei Zhao, Edward Marschall, Maxine Treisman, Alasdair McKay, Leo Padva, Max Crüsemann, David R. Nelson, David L. Steer, Ralf B. Schittenhelm, Julien Tailhades,et al.
Wiley
AbstractWe report our investigation of the utility of peptide crosslinking cytochrome P450 enzymes from biarylitide biosynthesis to generate a range of cyclic tripeptides from simple synthons. The crosslinked tripeptides produced by this P450 include both tyrosine‐histidine (A−N−B) and tyrosine‐tryptophan (A−O−B) crosslinked tripeptides, the latter a rare example of a phenolic crosslink to an indole moiety. Tripeptides are easily isolated following proteolytic removal of the leader peptide and can incorporate a wide range of amino acids in the residue inside the crosslinked tripeptide. Given the utility of peptide crosslinks in important natural products and the synthetic challenge that these can represent, P450 enzymes have the potential to play roles as important tools in the generation of high‐value cyclic tripeptides for incorporation in synthesis, which can be yet further diversified using selective chemical techniques through specific handles contained within these tripeptides.
Julien Tailhades
Springer Science and Business Media LLC
Jennifer A. E. Payne, Julien Tailhades, Felix Ellett, Xenia Kostoulias, Alex J. Fulcher, Ting Fu, Ryan Leung, Stephanie Louch, Amy Tran, Severin A. Weber,et al.
Springer Science and Business Media LLC
AbstractThe pathogenStaphylococcus aureuscan readily develop antibiotic resistance and evade the human immune system, which is associated with reduced levels of neutrophil recruitment. Here, we present a class of antibacterial peptides with potential to act both as antibiotics and as neutrophil chemoattractants. The compounds, which we term ‘antibiotic-chemoattractants’, consist of a formylated peptide (known to act as chemoattractant for neutrophil recruitment) that is covalently linked to the antibiotic vancomycin (known to bind to the bacterial cell wall). We use a combination of in vitro assays, cellular assays, infection-on-a-chip and in vivo mouse models to show that the compounds improve the recruitment, engulfment and killing ofS. aureusby neutrophils. Furthermore, optimizing the formyl peptide sequence can enhance neutrophil activity through differential activation of formyl peptide receptors. Thus, we propose antibiotic-chemoattractants as an alternate approach for antibiotic development.
Thierry Izoré, Y. T. Candace Ho, Joe A. Kaczmarski, Athina Gavriilidou, Ka Ho Chow, David L. Steer, Robert J. A. Goode, Ralf B. Schittenhelm, Julien Tailhades, Manuela Tosin,et al.
Springer Science and Business Media LLC
AbstractNon-ribosomal peptide synthetases are important enzymes for the assembly of complex peptide natural products. Within these multi-modular assembly lines, condensation domains perform the central function of chain assembly, typically by forming a peptide bond between two peptidyl carrier protein (PCP)-bound substrates. In this work, we report structural snapshots of a condensation domain in complex with an aminoacyl-PCP acceptor substrate. These structures allow the identification of a mechanism that controls access of acceptor substrates to the active site in condensation domains. The structures of this complex also allow us to demonstrate that condensation domain active sites do not contain a distinct pocket to select the side chain of the acceptor substrate during peptide assembly but that residues within the active site motif can instead serve to tune the selectivity of these central biosynthetic domains.
Yongwei Zhao, Y. T. Candace Ho, Julien Tailhades, and Max Cryle
Wiley
AbstractThe glycopeptide antibiotics (GPAs) are a fascinating example of complex natural product biosynthesis, with the nonribosomal synthesis of the peptide core coupled to a cytochrome P450‐mediated cyclisation cascade that crosslinks aromatic side chains within this peptide. Given that the challenges associated with the synthesis of GPAs stems from their highly crosslinked structure, there is great interest in understanding how biosynthesis accomplishes this challenging set of transformations. In this regard, the use of in vitro experiments has delivered important insights into this process, including the identification of the unique role of the X‐domain as a platform for P450 recruitment. In this minireview, we present an analysis of the results of in vitro studies into the GPA cyclisation cascade that have demonstrated both the tolerances and limitations of this process for modified substrates, and in turn developed rules for the future reengineering of this important antibiotic class.
Milda Kaniusaite, Julien Tailhades, Tiia Kittilä, Christopher D. Fage, Robert J.A. Goode, Ralf B. Schittenhelm, and Max J. Cryle
Wiley
The biosynthesis of the glycopeptide antibiotics (GPAs) demonstrates the exceptional ability of nonribosomal peptide (NRP) synthesis to generate diverse and complex structures from an expanded array of amino acid precursors. Whilst the heptapeptide cores of GPAs share a conserved C terminus, including the aromatic residues involved cross‐linking and that are essential for the antibiotic activity of GPAs, most structural diversity is found within the N terminus of the peptide. Furthermore, the origin of the (D)‐stereochemistry of residue 1 of all GPAs is currently unclear, despite its importance for antibiotic activity. Given these important features, we have now reconstituted modules (M) 1–4 of the NRP synthetase (NRPS) assembly lines that synthesise the clinically relevant type IV GPA teicoplanin and the related compound A40926. Our results show that important roles in amino acid modification during the NRPS‐mediated biosynthesis of GPAs can be ascribed to the actions of condensation domains present within these modules, including the incorporation of (D)‐amino acids at position 1 of the peptide. Our results also indicate that hybrid NRPS assembly lines can be generated in a facile manner by mixing NRPS proteins from different systems and that uncoupling of peptide formation due to different rates of activity seen for NRPS modules can be controlled by varying the ratio of NRPS modules. Taken together, this indicates that NRPS assembly lines function as dynamic peptide assembly lines and not static megaenzyme complexes, which has significant implications for biosynthetic redesign of these important biosynthetic systems.
Praveen Praveen, Julien Tailhades, K. Johan Rosengren, Mengjie Liu, John D. Wade, Ross A. D. Bathgate, and Mohammed Akhter Hossain
American Chemical Society (ACS)
The receptor for the neuropeptide relaxin 3, relaxin family peptide 3 (RXFP3) receptor, is an attractive pharmacological target for the control of eating, addictive, and psychiatric behaviors. Several structure-activity relationship studies on both human relaxin 3 (containing 3 disulfide bonds) and its analogue A2 (two disulfide bonds) suggest that the C-terminal carboxylic acid of the tryptophan residue in the B-chain is important for RXFP3 activity. In this study, we have added amide, alcohol, carbamate, and ester functionalities to the C-terminus of A2 and compared their structures and functions. As expected, the C-terminal amide form of A2 showed lower binding affinity for RXFP3 while ester and alcohol substitutions also demonstrated lower affinity. However, while these analogues showed slightly lower binding affinity, there was no significant difference in activation of RXFP3 compared to A2 bearing a C-terminal carboxylic acid, suggesting the binding pocket is able to accommodate additional atoms.
Milda Kaniusaite, Robert J. A. Goode, Julien Tailhades, Ralf B. Schittenhelm, and Max J. Cryle
Royal Society of Chemistry (RSC)
Redesign of the non-ribosomal peptide synthetase (NRPS) from teicoplanin biosynthesis has been extensively investigated via domain exchange, interface reengineering and through engineering communication between isolated NRPS modules.
Julien Tailhades, Yongwei Zhao, Y. T. Candace Ho, Anja Greule, Iftekhar Ahmed, Melanie Schoppet, Ketav Kulkarni, Rob J. A. Goode, Ralf B. Schittenhelm, James J. De Voss,et al.
Wiley
AbstractGlycopeptide antibiotics (GPAs) are important antibiotics that are highly challenging to synthesise due to their unique and heavily crosslinked structure. Given this, the synthetic production and diversification of this key compound class remains impractical. Furthermore, the possibility of biosynthetic reengineering of GPAs is not yet feasible since the selectivity of the biosynthetic crosslinking enzymes for altered substrates is largely unknown. We show that combining peptide synthesis with enzymatic cyclisation enables the formation of novel examples of GPAs and provides an indication of the utility of these crucial enzymes. By accessing the biosynthetic process in vitro, we identified peptide modifications that are enzymatically tolerated and can also reveal the mechanistic basis for substrate intolerance where present. Using this approach, we next specifically activated modified residues within GPAs for functionalisation at previously inaccessible positions, thereby offering the possibility of late‐stage chemical functionalisation after GPA cyclisation is complete.
Yongwei Zhao, Robert J. A. Goode, Ralf B. Schittenhelm, Julien Tailhades, and Max J. Cryle
American Chemical Society (ACS)
The glycopeptide antibiotics (GPAs) serve as an important example of the interplay of two powerful enzymatic classes in secondary metabolism: the coupling of non-ribosomal peptide synthesis with oxidative aromatic crosslinking performed by cytochrome P450 enzymes. This interplay is responsible for the generation of the highly crosslinked peptide aglycone at the core of this compound class that is required for antibiotic activity, and as such serves as an important point for the exploration of chemoenzymatic routes to understand the selectivity and mechanism of this complex cascade. Here, we demonstrate the effective reconstitution of enzymatic tetracyclization of synthetic teicoplanin-derived heptapeptides, and furthermore discern the importance of the OxyE enzyme in maintaining effective cyclization of such peptides bearing 3,5-dihydroxyphenylglycine residues at position 3 in their structures. These results demonstrate the value of chemically synthesized probes for the elucidation of the enzyme mechanism underpinning the complex process of GPA cyclization, and furthermore show the utility of the technique to probe the cyclization of non-natural GPA peptides by these powerful biosynthetic enzymes.
Edward Marschall, Max J. Cryle, and Julien Tailhades
Elsevier BV
Since the discovery of vancomycin in the 1950s, the glycopeptide antibiotics (GPAs) have been of great interest to the scientific community. These nonribosomally biosynthesized peptides are highly cross-linked, often glycosylated, and inhibit bacterial cell wall assembly by interfering with peptidoglycan synthesis. Interest in glycopeptide antibiotics covers many scientific disciplines, due to their challenging total syntheses, complex biosynthesis pathways, mechanism of action, and high potency. After intense efforts, early enthusiasm has given way to a recognition of the challenges in chemically synthesizing GPAs and of the effort needed to study and modify GPA-producing strains to prepare new GPAs to address the increasing threat of microbial antibiotic resistance. Although the preparation of GPAs, either by modifying the pendant groups such as saccharides or by functionalizing the N- or C-terminal moieties, is readily achievable, the peptide core of these molecules—the GPA aglycone—remains highly challenging to modify. This review aims to present a summary of the results of GPA modification obtained with the three major approaches developed to date: in vivo strain manipulation, total chemical synthesis, and chemoenzymatic synthesis methods.
Anja Greule, Thierry Izoré, Dumitrita Iftime, Julien Tailhades, Melanie Schoppet, Yongwei Zhao, Madeleine Peschke, Iftekhar Ahmed, Andreas Kulik, Martina Adamek,et al.
Springer Science and Business Media LLC
AbstractKistamicin is a divergent member of the glycopeptide antibiotics, a structurally complex class of important, clinically relevant antibiotics often used as the last resort against resistant bacteria. The extensively crosslinked structure of these antibiotics that is essential for their activity makes their chemical synthesis highly challenging and limits their production to bacterial fermentation. Kistamicin contains three crosslinks, including an unusual 15-membered A-O-B ring, despite the presence of only two Cytochrome P450 Oxy enzymes thought to catalyse formation of such crosslinks within the biosynthetic gene cluster. In this study, we characterise the kistamicin cyclisation pathway, showing that the two Oxy enzymes are responsible for these crosslinks within kistamicin and that they function through interactions with the X-domain, unique to glycopeptide antibiotic biosynthesis. We also show that the kistamicin OxyC enzyme is a promiscuous biocatalyst, able to install multiple crosslinks into peptides containing phenolic amino acids.
Julien Tailhades, Yongwei Zhao, Melanie Schoppet, Anja Greule, Robert J. A. Goode, Ralf B. Schittenhelm, James J. De Voss, and Max J. Cryle
American Chemical Society (ACS)
Natural products are the greatest source of antimicrobial agents, although their structural complexity often renders synthetic production and diversification of key classes impractical. One pertinent example is the glycopeptide antibiotics (GPAs), which are highly challenging to synthesize due to their heavily cross-linked structures. Here, we report an optimized method that generates >75% tricyclic peptides from synthetic precursors in order to explore the acceptance of novel GPA precursor peptides by these key existent biosynthetic enzymes.
Nitin A. Patil, John A. Karas, John D. Wade, Mohammed Akhter Hossain, and Julien Tailhades
Wiley
AbstractStructure–activity relationship studies are a highly time‐consuming aspect of peptide‐based drug development, particularly in the assembly of disulfide‐rich peptides, which often requires multiple synthetic steps and purifications. Therefore, it is vital to develop rapid and efficient chemical methods to readily access the desired peptides. We have developed a photolysis‐mediated “one‐pot” strategy for regioselective disulfide bond formation. The new pairing system utilises two ortho‐nitroveratryl protected cysteines to generate two disulfide bridges in less than one hour in good yield. This strategy was applied to the synthesis of complex disulfide‐rich peptides such as Rho‐conotoxin ρ‐TIA and native human insulin.
Thierry Izoré, Julien Tailhades, Mathias Henning Hansen, Joe A. Kaczmarski, Colin J. Jackson, and Max J. Cryle
Proceedings of the National Academy of Sciences
The protein Ebony from Drosophila melanogaster plays a central role in the regulation of histamine and dopamine in various tissues through condensation of these amines with β-alanine. Ebony is a rare example of a nonribosomal peptide synthetase (NRPS) from a higher eukaryote and contains a C-terminal sequence that does not correspond to any previously characterized NRPS domain. We have structurally characterized this C-terminal domain and have discovered that it adopts the aryl-alkylamine- N -acetyl transferase (AANAT) fold, which is unprecedented in NRPS biology. Through analysis of ligand-bound structures, activity assays, and binding measurements, we have determined how this atypical condensation domain is able to provide selectivity for both the carrier protein-bound amino acid and the amine substrates, a situation that remains unclear for standard condensation domains identified to date from NRPS assembly lines. These results demonstrate that the C terminus of Ebony encodes a eukaryotic example of an alternative type of NRPS condensation domain; they also illustrate how the catalytic components of such assembly lines are significantly more diverse than a minimal set of conserved functional domains.
Milda Kaniusaite, Julien Tailhades, Edward A. Marschall, Robert J. A. Goode, Ralf B. Schittenhelm, and Max J. Cryle
Royal Society of Chemistry (RSC)
A complex interplay of non-ribosomal peptide synthetase domains works together with trans-acting enzymes to ensure effective GPA biosynthesis.
Melanie Schoppet, Julien Tailhades, Ketav Kulkarni, and Max J. Cryle
American Chemical Society (ACS)
Natural products such as the glycopeptide antibiotics (GPAs, including vancomycin and teicoplanin) are of great pharmaceutical importance due to their use against Gram-positive bacteria such as methicillin-resistant Staphylococcus aureus. GPAs are assembled in a complex process based on nonribosomal peptide synthesis and late-stage, multistep cross-linking of the linear heptapeptide performed by cytochrome P450 monooxygenases. These P450 enzymes demonstrate varying degrees of substrate selectivity toward the linear peptide precursor, with limited information available about their tolerance regarding modifications to amino acid residues within the essential antibiotic core of the GPA. In order to test the acceptance of altered residues by the P450-catalyzed cyclization cascade, we have explored the use of β-amino acids in both variable and highly conserved positions within GPA peptides. Our results indicate that the incorporation of β-amino acids at the C-terminus of the peptide leads to a dramatic reduction in the efficiency of peptide cyclization by the P450s during GPA biosynthesis, whereas replacement of residue 3 is well tolerated by the same enzymes. These results show that maintaining the C-terminal 3,5-dihydroxyphenylglycine residue is of key importance to maintain the efficiency of this complex and essential enzymatic cross-linking process.