1
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Wasko J, Wolszczak M, Zajaczkowska Z, Dudek M, Kolesinska B. Human serum albumin as a potential drug delivery system for N-methylated hot spot insulin analogs inhibiting hormone aggregation. Bioorg Chem 2024; 143:107104. [PMID: 38194903 DOI: 10.1016/j.bioorg.2024.107104] [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] [Received: 09/13/2023] [Revised: 12/20/2023] [Accepted: 01/03/2024] [Indexed: 01/11/2024]
Abstract
The purpose of this study was to investigate whether Human Serum Albumin (HSA) can bind N-methylated analogs of hot spots of native insulin. Three N-methylated derivatives of the A13-A19 fragment of native insulin were used: L(N-Me)YQLENY (1), LYQ(N-Me)LENY (2), and L(N-Me)YQ(N-Me)LENY (3). The studied N-methylated insulin fragments possess inhibiting potential against hormone aggregation. A variety of research techniques, including spectroscopic methods and microscopy assays, were used to study the interaction of HSA with the N-methylated insulin fragments. Based on spectroscopic measurements with Congo Red and Thioflavin T, all the analyzed N-methylated peptides were able to interact with the HSA surface. The CD spectrum registered for HSA in the presence of L(N-Me)YQLENY showed the smallest content of α-helix conformation, indicating the most compact HSA structure. Based on the results of MST, the dissociation constants (Kd) for complexes of HSA and peptides 1-3 were 19.2 nM (complex 1), 15.6 nM (complex 2), and 8.07 nM (complex 3). Microscopy assays, dynamic light scattering measurements as well as computer simulation of protein-ligand interaction also confirmed the possibility of docking the N-methylated inhibitors within HSA.
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Affiliation(s)
- Joanna Wasko
- Institute of Organic Chemistry, Faculty of Chemistry, Lodz University of Technology, Zeromskiego 116, Poland.
| | - Marian Wolszczak
- Institute of Applied Radiation Chemistry, Faculty of Chemistry, Lodz University of Technology, Wroblewskiego 15, Poland.
| | - Zuzanna Zajaczkowska
- Institute of Organic Chemistry, Faculty of Chemistry, Lodz University of Technology, Zeromskiego 116, Poland.
| | - Mariusz Dudek
- Institute of Materials Science and Engineering, The Faculty of Mechanical Engineering, Lodz University of Technology, Stefanowskiego 1/15, Poland.
| | - Beata Kolesinska
- Institute of Organic Chemistry, Faculty of Chemistry, Lodz University of Technology, Zeromskiego 116, Poland.
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2
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Crone KK, Jomori T, Miller FS, Gralnick JA, Elias MH, Freeman MF. RiPP enzyme heterocomplex structure-guided discovery of a bacterial borosin α- N-methylated peptide natural product. RSC Chem Biol 2023; 4:804-816. [PMID: 37799586 PMCID: PMC10549244 DOI: 10.1039/d3cb00093a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Accepted: 08/18/2023] [Indexed: 10/07/2023] Open
Abstract
Amide peptide backbone methylation is a characteristic post-translational modification found in a family of ribosomally synthesized and post-translationally modified peptide natural products (RiPPs) called borosins. Previously, we bioinformatically identified >1500 putative borosin pathways in bacteria; however, none of the pathways were associated with a known secondary metabolite. Through in-depth characterization of a borosin pathway in Shewanella oneidensis MR-1, we have now identified a bacterially derived borosin natural product named Shewanellamide A. Borosin identification was facilitated by the creation and analysis of a series of precursor variants and crystallographic interrogation of variant precursor and methyltransferase complexes. Along with assaying two proteases from S. oneidensis, probable boundaries for proteolytic maturation of the metabolite were projected and confirmed via comparison of S. oneidensis knockout and overexpression strains. All in all, the S. oneidensis natural product was found to be a 16-mer linear peptide featuring two backbone methylations, establishing Shewanellamide A as one of the few borosin metabolites yet identified, and the first from bacteria.
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Affiliation(s)
- K K Crone
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota - Twin Cities St. Paul 55108 USA
| | - T Jomori
- The BioTechnology Institute, University of Minnesota - Twin Cities St. Paul 55108 USA
| | - F S Miller
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota - Twin Cities St. Paul 55108 USA
| | - J A Gralnick
- The BioTechnology Institute, University of Minnesota - Twin Cities St. Paul 55108 USA
- Department of Plant and Microbial Biology, University of Minnesota - Twin Cities St. Paul 55108 USA
| | - M H Elias
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota - Twin Cities St. Paul 55108 USA
- The BioTechnology Institute, University of Minnesota - Twin Cities St. Paul 55108 USA
| | - M F Freeman
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota - Twin Cities St. Paul 55108 USA
- The BioTechnology Institute, University of Minnesota - Twin Cities St. Paul 55108 USA
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3
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Bhowmick J, Nag M, Ghosh P, Rajmani RS, Chatterjee R, Karmakar K, Chandra K, Chatterjee J, Chakravortty D, Varadarajan R. A CcdB toxin-derived peptide acts as a broad-spectrum antibacterial therapeutic in infected mice. EMBO Rep 2023; 24:e55338. [PMID: 37166011 PMCID: PMC10328072 DOI: 10.15252/embr.202255338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Revised: 04/16/2023] [Accepted: 04/21/2023] [Indexed: 05/12/2023] Open
Abstract
The bacterial toxin CcdB (Controller of Cell death or division B) targets DNA Gyrase, an essential bacterial topoisomerase, which is also the molecular target for fluoroquinolones. Here, we present a short cell-penetrating 24-mer peptide, CP1-WT, derived from the Gyrase-binding region of CcdB and examine its effect on growth of Escherichia coli, Salmonella Typhimurium, Staphylococcus aureus and a carbapenem- and tigecycline-resistant strain of Acinetobacter baumannii in both axenic cultures and mouse models of infection. The CP1-WT peptide shows significant improvement over ciprofloxacin in terms of its in vivo therapeutic efficacy in treating established infections of S. Typhimurium, S. aureus and A. baumannii. The molecular mechanism likely involves inhibition of Gyrase or Topoisomerase IV, depending on the strain used. The study validates the CcdB binding site on bacterial DNA Gyrase as a viable and alternative target to the fluoroquinolone binding site.
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Grants
- Department of Biotechnology, Ministry of Science and Technology, India - Indian Institute of Science (DBT-IISc) partnership program
- BT/COE/34/SP15219/2015 Department of Biotechnology, Ministry of Science and Technology, India
- DT.20/11/2015 Department of Biotechnology, Ministry of Science and Technology, India
- Department of Science and Technology, Ministry of Science and Technology, India (DST FIST)
- Ministry of Education, India (MHRD)
- University Grants Commission, Ministry of Education, India (UGC Centre for Advanced Studies)
- Department of Biotechnology, Ministry of Science and Technology, India
- Ministry of Education, India (MHRD)
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Affiliation(s)
- Jayantika Bhowmick
- Molecular Biophysics Unit (MBU)Indian Institute of ScienceBangaloreIndia
| | - Manish Nag
- Molecular Biophysics Unit (MBU)Indian Institute of ScienceBangaloreIndia
| | - Pritha Ghosh
- Molecular Biophysics Unit (MBU)Indian Institute of ScienceBangaloreIndia
| | - Raju S Rajmani
- Molecular Biophysics Unit (MBU)Indian Institute of ScienceBangaloreIndia
| | - Ritika Chatterjee
- Department of Microbiology and Cell BiologyIndian Institute of ScienceBangaloreIndia
| | - Kapudeep Karmakar
- Department of Microbiology and Cell BiologyIndian Institute of ScienceBangaloreIndia
| | - Kasturi Chandra
- Department of Microbiology and Cell BiologyIndian Institute of ScienceBangaloreIndia
| | - Jayanta Chatterjee
- Molecular Biophysics Unit (MBU)Indian Institute of ScienceBangaloreIndia
| | - Dipshikha Chakravortty
- Department of Microbiology and Cell BiologyIndian Institute of ScienceBangaloreIndia
- School of BiologyIndian Institute of Science Education and Research Thiruvananthapuram (IISER TVM)ThiruvananthapuramIndia
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4
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Kumari T, Verma DP, Kuldeep J, Dhanabal VB, Verma NK, Sahai R, Tripathi AK, Saroj J, Ali M, Mitra K, Siddiqi MI, Bhattacharjya S, Ghosh JK. 10-Residue MyD88-Peptide Adopts β-Sheet Structure, Self-Assembles, Binds to Lipopolysaccharides, and Rescues Mice from Endotoxin-Mediated Lung-Infection and Death. ACS Chem Biol 2022; 17:3420-3434. [PMID: 36367958 DOI: 10.1021/acschembio.2c00569] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Naturally occurring cationic antimicrobial peptides (AMPs) mostly adopt α-helical structures in bacterial membrane mimetic environments. To explore the design of novel β-sheet AMPs, we identified two short cationic amphipathic β-strand segments from the crystal structure of the innate immune protein, MyD88. Interestingly, of these, the 10-residue arginine-valine-rich synthetic MyD88-segment, KRCRRMVVVV (M3), exhibited β-sheet structure when bound to the outer membrane Gram-negative bacterial component, LPS. Isothermal titration calorimetric data showed that M3 bound to LPS with high affinity, and the interaction was hydrophobic in nature. Supporting these observations, computational studies indicated strong interactions of multiple and consecutive valine residues of M3 with the acyl chain of LPS. Moreover, M3 adopted nanosheet and nanofibrillar structure in 25% acetonitrile/water and isopropanol, respectively. M3 showed substantial antibacterial activities against both Gram-positive and Gram-negative bacteria which it appreciably retained in the presence of human serum and physiological salts. M3 was non-hemolytic against human red blood cells and non-cytotoxic to 3T3 cells up to 200 μM and to mice in vivo at a dose of 40 mg/kg. Furthermore, M3 neutralized LPS-induced pro-inflammatory responses in THP-1 cells and rat bone marrow-derived macrophages. Consequently, M3 attenuated LPS-mediated lung inflammation in mice and rescued them (80% survival at 10 mg/kg dose) against a lethal dose of LPS. The results demonstrate the identification of a 10-mer LPS-interacting, β-sheet peptide from MyD88 with the ability to form nanostructures and in vivo activity against LPS challenge in mice. The identified M3-template provides scope for designing novel bioactive peptides with β-sheet structures and self-assembling properties.
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Affiliation(s)
- Tripti Kumari
- Biochemistry and Structural Biology Division, CDRI, Lucknow 226031, India
| | | | - Jitendra Kuldeep
- Biochemistry and Structural Biology Division, CDRI, Lucknow 226031, India
| | | | - Neeraj Kumar Verma
- Biochemistry and Structural Biology Division, CDRI, Lucknow 226031, India
| | - Rohit Sahai
- Electron Microscopy Unit, CDRI, Lucknow 226031, India
| | | | - Jyotshana Saroj
- Biochemistry and Structural Biology Division, CDRI, Lucknow 226031, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh 201002, India
| | - Mehmood Ali
- Biochemistry and Structural Biology Division, CDRI, Lucknow 226031, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh 201002, India
| | - Kalyan Mitra
- Electron Microscopy Unit, CDRI, Lucknow 226031, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh 201002, India
| | - Mohammad Imran Siddiqi
- Biochemistry and Structural Biology Division, CDRI, Lucknow 226031, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh 201002, India
| | - Surajit Bhattacharjya
- School of Biological Sciences, Nanyang Technological University, Singapore 639798, Singapore
| | - Jimut Kanti Ghosh
- Biochemistry and Structural Biology Division, CDRI, Lucknow 226031, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh 201002, India
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5
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Kelly CN, Townsend CE, Jain AN, Naylor MR, Pye CR, Schwochert J, Lokey RS. Geometrically Diverse Lariat Peptide Scaffolds Reveal an Untapped Chemical Space of High Membrane Permeability. J Am Chem Soc 2021; 143:705-714. [PMID: 33381960 PMCID: PMC8514148 DOI: 10.1021/jacs.0c06115] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Constrained, membrane-permeable peptides offer the possibility of engaging challenging intracellular targets. Structure-permeability relationships have been extensively studied in cyclic peptides whose backbones are cyclized from head to tail, like the membrane permeable and orally bioavailable natural product cyclosporine A. In contrast, the physicochemical properties of lariat peptides, which are cyclized from one of the termini onto a side chain, have received little attention. Many lariat peptide natural products exhibit interesting biological activities, and some, such as griselimycin and didemnin B, are membrane permeable and have intracellular targets. To investigate the structure-permeability relationships in the chemical space exemplified by these natural products, we generated a library of scaffolds using stable isotopes to encode stereochemistry and determined the passive membrane permeability of over 1000 novel lariat peptide scaffolds with molecular weights around 1000. Many lariats were surprisingly permeable, comparable to many known orally bioavailable drugs. Passive permeability was strongly dependent on N-methylation, stereochemistry, and ring topology. A variety of structure-permeability trends were observed including a relationship between alternating stereochemistry and high permeability, as well as a set of highly permeable consensus sequences. For the first time, robust structure-permeability relationships are established in synthetic lariat peptides exceeding 1000 compounds.
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Affiliation(s)
- Colin N. Kelly
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, USA
| | - Chad E. Townsend
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, USA
| | - Ajay N. Jain
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, USA
| | - Matthew R. Naylor
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, USA
| | | | | | - R. Scott Lokey
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, USA
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6
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Hall AJ, Haskali MB. Radiolabelled Peptides: Optimal Candidates for Theranostic Application in Oncology. Aust J Chem 2021. [DOI: 10.1071/ch21118] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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7
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An S/T motif controls reversible oligomerization of the Hsp40 chaperone DNAJB6b through subtle reorganization of a β sheet backbone. Proc Natl Acad Sci U S A 2020; 117:30441-30450. [PMID: 33199640 DOI: 10.1073/pnas.2020306117] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Chaperone oligomerization is often a key aspect of their function. Irrespective of whether chaperone oligomers act as reservoirs for active monomers or exhibit a chaperoning function themselves, understanding the mechanism of oligomerization will further our understanding of how chaperones maintain the proteome. Here, we focus on the class-II Hsp40, human DNAJB6b, a highly efficient inhibitor of protein self-assembly in vivo and in vitro that forms functional oligomers. Using single-quantum methyl-based relaxation dispersion NMR methods we identify critical residues for DNAJB6b oligomerization in its C-terminal domain (CTD). Detailed solution NMR studies on the structure of the CTD showed that a serine/threonine-rich stretch causes a backbone twist in the N-terminal β strand, stabilizing the monomeric form. Quantitative analysis of an array of NMR relaxation-based experiments (including Carr-Purcell-Meiboom-Gill relaxation dispersion, off-resonance R 1ρ profiles, lifetime line broadening, and exchange-induced shifts) on the CTD of both wild type and a point mutant (T142A) within the S/T region of the first β strand delineates the kinetics of the interconversion between the major twisted-monomeric conformation and a more regular β strand configuration in an excited-state dimer, as well as exchange of both monomer and dimer species with high-molecular-weight oligomers. These data provide insights into the molecular origins of DNAJB6b oligomerization. Further, the results reported here have implications for the design of β sheet proteins with tunable self-assembling properties and pave the way to an atomic-level understanding of amyloid inhibition.
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8
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Jwad R, Weissberger D, Hunter L. Strategies for Fine-Tuning the Conformations of Cyclic Peptides. Chem Rev 2020; 120:9743-9789. [PMID: 32786420 DOI: 10.1021/acs.chemrev.0c00013] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Cyclic peptides are promising scaffolds for drug development, attributable in part to their increased conformational order compared to linear peptides. However, when optimizing the target-binding or pharmacokinetic properties of cyclic peptides, it is frequently necessary to "fine-tune" their conformations, e.g., by imposing greater rigidity, by subtly altering certain side chain vectors, or by adjusting the global shape of the macrocycle. This review systematically examines the various types of structural modifications that can be made to cyclic peptides in order to achieve such conformational control.
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Affiliation(s)
- Rasha Jwad
- Department of Chemistry, College of Science, Al-Nahrain University, Baghdad, Iraq
| | - Daniel Weissberger
- School of Chemistry, University of New South Wales (UNSW) Sydney, New South Wales 2052, Australia
| | - Luke Hunter
- School of Chemistry, University of New South Wales (UNSW) Sydney, New South Wales 2052, Australia
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9
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Hautier A, Carvalho T, Valensin D, Simaan AJ, Faure B, Mateus P, Delgado R, Iranzo O. The role of methylation in the copper(ii) coordination properties of a His-containing decapeptide. Dalton Trans 2019; 48:1859-1870. [DOI: 10.1039/c8dt05037f] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
N-Methylation: a simple strategy to stabilize copper species lacking amidate coordination at neutral pH value.
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Affiliation(s)
| | | | - Daniela Valensin
- Dipartimento di Biotecnologie
- Chimica e Farmacia
- Università di Siena
- 53100 Siena
- Italy
| | | | - Bruno Faure
- Aix Marseille Univ
- CNRS
- Centrale Marseille
- iSm2
- Marseille
| | - Pedro Mateus
- Instituto de Tecnologia Química e Biológica António Xavier
- Universidade Nova de Lisboa
- 2780-157 Oeiras
- Portugal
| | - Rita Delgado
- Instituto de Tecnologia Química e Biológica António Xavier
- Universidade Nova de Lisboa
- 2780-157 Oeiras
- Portugal
| | - Olga Iranzo
- Aix Marseille Univ
- CNRS
- Centrale Marseille
- iSm2
- Marseille
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10
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Lahiri P, Verma H, Ravikumar A, Chatterjee J. Protein stabilization by tuning the steric restraint at the reverse turn. Chem Sci 2018; 9:4600-4609. [PMID: 29899953 PMCID: PMC5969505 DOI: 10.1039/c7sc05163h] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Accepted: 04/24/2018] [Indexed: 11/23/2022] Open
Abstract
The incorporation of pseudoallylic strain by N-methylation at the solvent exposed loop in proteins leads to a stark increase in their thermodynamic stability that can be tuned by altering the amino acid composition.
Reverse turns are solvent-exposed motifs in proteins that are crucial in nucleating β-sheets and drive the protein folding. The solvent-exposed nature makes reverse turns more amenable to chemical modifications than α-helices or β-sheets towards modulating the stability of re-engineered proteins. Here, we utilize van der Waals repulsive forces in tuning the steric restraint at the reverse turn. The steric restraint induced upon N-methylation of the i+1–i+2 amide bond at the reverse turn results in well-folded and stable β-sheets in aqueous solution at room temperature. The developed superactive turn inducing motif is tolerant to a wide variety of functional groups present on coded amino acids making the designed turn fully compatible with bioactive loops in proteins. We demonstrate that the steric restraint and the functional groups at the reverse turn act in synergy to modulate the folding of re-engineered β-sheets. Introduction of the turn motifs onto a three-stranded β-sheet protein, Pin 1 WW domain, resulted in various analogs showing a cooperative two-state transition with thermal stability (TM) ranging from 62 °C to 82 °C. Despite modulating the stability of Pin 1 variants by ∼2.8 kcal mol–1 (ΔΔGf), the native fold in all the protein variants was found to be unperturbed. This structural stability is brought about by conformational preorganization at the engineered reverse turn that results in strong intramolecular hydrogen bonds along the three dimensional structure of the protein. Thus, this simple loop engineering strategy via two amino acid substitution provides us a “toolkit” to modulate the stability of β-sheet containing peptides and proteins in aqueous solution that will greatly expand the scope of de novo protein and foldamer design.
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Affiliation(s)
- Priyanka Lahiri
- Molecular Biophysics Unit , Indian Institute of Science , Bangalore 560012 , India .
| | - Hitesh Verma
- Molecular Biophysics Unit , Indian Institute of Science , Bangalore 560012 , India .
| | - Ashraya Ravikumar
- Molecular Biophysics Unit , Indian Institute of Science , Bangalore 560012 , India .
| | - Jayanta Chatterjee
- Molecular Biophysics Unit , Indian Institute of Science , Bangalore 560012 , India .
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11
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Slough DP, Yu H, McHugh SM, Lin YS. Toward accurately modeling N-methylated cyclic peptides. Phys Chem Chem Phys 2018; 19:5377-5388. [PMID: 28155950 DOI: 10.1039/c6cp07700e] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Cyclic peptides have unique properties and can target protein surfaces specifically and potently. N-Methylation provides a promising way to further optimize the pharmacokinetic and structural profiles of cyclic peptides. The capability to accurately model structures adopted by N-methylated cyclic peptides would facilitate rational design of this interesting and useful class of molecules. We apply molecular dynamics simulations with advanced enhanced sampling methods to efficiently characterize the structural ensembles of N-methylated cyclic peptides, while simultaneously evaluating the overall performance of several simulation force fields. We find that one of the residue-specific force fields, RSFF2, is able to recapitulate experimental structures of the N-methylated cyclic peptide benchmarks tested here when the correct amide isomers are used as initial configurations and enforced during the simulations. Thus, using our simulation approach, it is possible to accurately and efficiently predict the structures of N-methylated cyclic peptides if sufficient information is available to determine the correct amide cis/trans configuration. Moreover, our results suggest that, upon further optimization of RSFF2 to more reliably predict cis/trans isomers, molecular dynamics simulations will be able to de novo predict N-methylated cyclic peptides in the near future, strongly motivating such continued optimization.
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Affiliation(s)
- Diana P Slough
- Department of Chemistry, Tufts University, Medford, Massachusetts 02155, USA.
| | - Hongtao Yu
- Department of Chemistry, Tufts University, Medford, Massachusetts 02155, USA.
| | - Sean M McHugh
- Department of Chemistry, Tufts University, Medford, Massachusetts 02155, USA.
| | - Yu-Shan Lin
- Department of Chemistry, Tufts University, Medford, Massachusetts 02155, USA.
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12
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Cameron AJ, Squire CJ, Edwards PJB, Harjes E, Sarojini V. Crystal and NMR Structures of a Peptidomimetic β-Turn That Provides Facile Synthesis of 13-Membered Cyclic Tetrapeptides. Chem Asian J 2017; 12:3195-3202. [PMID: 29098772 DOI: 10.1002/asia.201701422] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Revised: 10/30/2017] [Indexed: 12/31/2022]
Abstract
Herein we report the unique conformations adopted by linear and cyclic tetrapeptides (CTPs) containing 2-aminobenzoic acid (2-Abz) in solution and as single crystals. The crystal structure of the linear tetrapeptide H2 N-d-Leu-d-Phe-2-Abz-d-Ala-COOH (1) reveals a novel planar peptidomimetic β-turn stabilized by three hydrogen bonds and is in agreement with its NMR structure in solution. While CTPs are often synthetically inaccessible or cyclize in poor yield, both 1 and its N-Me-d-Phe analogue (2) adopt pseudo-cyclic frameworks enabling near quantitative conversion to the corresponding CTPs 3 and 4. The crystal structure of the N-methylated peptide (4) is the first reported for a CTP containing 2-Abz and reveals a distinctly planar 13-membered ring, which is also evident in solution. The N-methylation of d-Phe results in a peptide bond inversion compared to the conformation of 3 in solution.
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Affiliation(s)
- Alan J Cameron
- School of Chemical Sciences, The University of Auckland, Auckland, 1142, New Zealand
| | - Christopher J Squire
- School of Biological Sciences, The University of Auckland, Auckland, 1142, New Zealand
| | - Patrick J B Edwards
- Institute of Fundamental Sciences, Massey University, Palmerston North, 4442, New Zealand
| | - Elena Harjes
- Institute of Fundamental Sciences, Massey University, Palmerston North, 4442, New Zealand
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