Daptomycin Synthesis via SPPS and Serine Ligation
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Solution Overview
Problem
Current methods for synthesizing daptomycin, a potent antibiotic effective against resistant Gram-positive pathogens, are challenging due to its complex structure and the presence of non-proteinogenic amino acids, making it difficult to produce efficient analogues for establishing structure-activity relationships.
Innovation Solution
A method combining solid phase peptide synthesis (SPPS) with solution phase synthesis and intramolecular Serine/Threonine ligation for macrocyclization, allowing for the precise assembly of daptomycin molecules and analogues, including the formation of Kynurenine residues through ozonolysis and modification of the lipid chain, to produce daptomycin and its analogues with structural flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional total synthesis methods are used for daptomycin, then the complete molecular structure can be obtained, but the synthesis process becomes extremely complex and inefficient due to the presence of non-proteinogenic amino acids and the 31-membered macrocyclic ring
Solution Approach 1:
The daptomycin molecule is divided into two segments: a linear peptide sequence synthesized by SPPS and a lipid tail added separately. The linear peptide contains all amino acid residues including non-proteinogenic ones, while the lipid is attached post-synthesis via ligation at the N-terminus, simplifying the overall synthesis process
Solution Approach 2:
The linear peptide sequence is pre-assembled on solid support using standard Fmoc-SPPS methodology with all protected amino acid residues in place before final deprotection and lipid attachment. This preliminary assembly allows for precise control of the peptide backbone while simplifying subsequent steps
2Adaptability or versatility
If genetic engineering of NRPS is used to produce daptomycin analogues, then biosynthetic pathways can be modified, but the structural flexibility and precision for establishing structure-activity relationships is limited
Solution Approach 1:
Individual amino acid residues in the linear peptide sequence can be selectively modified while maintaining the overall peptide structure. The SPPS approach allows for site-specific incorporation of different amino acids, enabling precise structure-activity relationship studies without requiring complete redesign of the biosynthetic pathway
Solution Approach 2:
The synthetic method can produce both daptomycin and its analogues using the same general protocol, with the ability to incorporate various amino acid residues including non-proteinogenic ones. This universal approach replaces the need for separate genetic engineering projects for each analogue
3Manufacturing precision
If chemo-enzymatic synthesis is used to modify lipid chain and ornithine δ-amino group, then specific modifications can be achieved, but the overall synthesis efficiency and flexibility for producing multiple analogues is reduced
Solution Approach 1:
The lipid tail is pre-synthesized with appropriate protection groups and then attached to the N-terminus of the linear peptide in a single ligation step. This preliminary preparation of the lipid component streamlines the overall synthesis compared to post-synthetic enzymatic modifications
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables the efficient synthesis of daptomycin and its analogues with high yield and purity, allowing for the exploration of structure-activity relationships and the production of effective variants, overcoming the challenges of daptomycin's complex structure and non-proteinogenic amino acids.
Implementation Method 1
Kynurenine residues are formed from by ozonolysis of tryptophan residues within an intermediate sequence
Implementation Method 2
Macrocyclization involves intramolecular Serine/Threonine ligation (STL) at the serine site of the sequence
Data Source
AI summary
A method for the synthesis of daptomycin or a daptomycin analog is carried out on a resin to form a linear precursor followed by a serine ligation macrocyclization in solution. Daptomycin analogs can differ from daptomycin by substitution of amino acids residues and/or deletion or addition of amino acid residues. Daptomycin analogs can include a different fatty acid in the side arm of the daptomycin analog.