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Explore the world of peptides, from natural to synthetic forms, detailing their structure, synthesis methods, and enhancement techniques. Learn about the significance of peptide design in biomedicine and drug development.
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Designing peptides: from nature to bench Crazy about biomedicine Júlia García Pindado
A brief reminder about proteins and peptides What’sanaminoacid? Chirality
A brief reminder about proteins and peptides How amino acids form proteins?
A brief reminder about proteins and peptides Protein structure
Peptides as drugs 40 marketed peptides (only 1%) 270 in clinical trials 15% year growth 400 in advanced preclinical trials
Peptides as drugs Biologics Small molecules Peptides Chemically well defined Low production cost Chemical synthesis Oral administration Specificity Specificity High production cost Non chemical synthesis Immunogenicity No oral administration Chemically well defined Oral administration Low cost of production Permeability through biological barriers No immunogenicity Specificity
Ideal drug candidate • Permeability through biological barriers reach the target • Stability • Solubility • Active (nM range) • Non toxic
Solid phase peptide synthesis (SPPS) Developed by Merrifield in 1963 • Fastdevelopment • Complexpeptides can be reached • 60-70% efficiency Microwave assisted SPPS Manual SPPS
Solid phase peptide synthesis (SPPS) Temporary protecting group Boc/BzlFmoc/tBu Permanent protecting group
Solid phase peptide synthesis (SPPS) • Resins • Size of theresinbeads (80-200 µm) • Mechanical and thermalstability • Price • Swelling • Types: • Cross-linkedpolysterene • Polyamide • Tentagel • Soluble
Solid phase peptide synthesis (SPPS) Resins Wang SWELLING 2-Chlorotrityl chloride Rink amide Chemmatrix
Solid phase peptide synthesis (SPPS) Couplingreagents
Solid phase peptide synthesis (SPPS) Protectinggroups
Solid phase peptide synthesis (SPPS) Protectinggroups
Solid phase peptide synthesis (SPPS) The concept of orthogonality Removeonlythedesired PG withoutaffectingtheothers
Solid phase peptides synthesis (SPPS) Teststocheckcouplingreactions Kaiser Free amines Chloranil
Solid phase peptides synthesis (SPPS) Sidereactions Diketopiperazine (DKP) Epimerization: losing the stereochemistry
Solid phase peptides synthesis (SPPS) Otherinconveniences Aggregation Deletion of residues Problems during the cleavage process
Solid phase peptides synthesis (SPPS) Purification Traditional chromatographic purification
Solid phase peptides synthesis (SPPS) Purification SPPS enables us to avoid performing several purification steps Reagents Solvent Impurities Beads with the peptide Beads of resin wash Reagents and byproducts
Solid phase peptides synthesis (SPPS) Purification HPLC can be used to separate the drug from all the other impurities
How can we improve synthetic peptides? WHY? To… - Increase stability - Enhance cell uptake and permeability through biological barriers - Improve resistance against proteases • N-methylatedpeptides • Non natural aminoacids • Cyclicpeptides • Stapledpeptides
How can we improve synthetic peptides? Proteases
Designing peptides • Synthesis of natural peptides • Synthesis of novel peptides
Mimicking nature Aromatic AA(Phe) Variable AA
Creating new sequences • Envisagingthedesiredproduct • Properselection of thestrategy • Resin • PG • Final removal of allthe PG? • Furtherreactions and/ordeprotectionsaftercleavage • Carryingoutthesynthesis
Selecting the resin… 2-Chlorotrityl: 1% TFA in DCM Protected peptide acid Wang: 95% TFA Peptide acid Rink amide Chemmatrix: 95% TFA Peptide amide
Choosing the suitable PG... Removal in acidicconditions: pNZ:1-6M SnCl2, 1.6mM HCl (dioxane) in DMF Trt: 1% TFA in DCM Boc:25-50% TFA tBu: 90% TFA Removal in basicconditions: Fmoc:20% piperidine/DMF Bzl: NaOH in organic solvents Removal in otherconditions: N3 Acm: I2 (S-S) Hg(II) (SH) Azide: PMe3 in dioxane Alloc: Pd(PPh)3 cat., scavengers PhSiH3 in organic solvents Al: Pd(PPh)3 cat., scavengers PhSiH3 in organic solvents
Analysis of the obtained product High Performance LiquidChromatography (HPLC)
Analysis of the obtained product Massspectrometry (MS)
Our lab (Giralt’s group) Design, synthesis and structure of peptides and proteins