The Stereocontrolled Biosynthesis of Mirror-Symmetric 2,4-Diaminobutyric Acid Homopolymers Is Critically Governed by Adenylation Activations
| Autor: | Hibiki Fukumoto, Kazuya Yamanaka, Tadao Oikawa, Yoshimitsu Hamano, Munenori Takehara |
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| Rok vydání: | 2020 |
| Předmět: |
0301 basic medicine
Stereochemistry In silico Racemases and Epimerases 01 natural sciences Biochemistry 03 medical and health sciences chemistry.chemical_compound Biosynthesis Bacterial Proteins Nonribosomal peptide Gene cluster Peptide Synthases Adenylylation Alanine chemistry.chemical_classification 010405 organic chemistry Aminobutyrates Stereoisomerism General Medicine Genomics Streptomyces 0104 chemical sciences Amino acid Actinobacteria 030104 developmental biology chemistry Multigene Family Peptide Biosynthesis Nucleic Acid-Independent Molecular Medicine Heterologous expression |
| Zdroj: | ACS chemical biology. 15(7) |
| ISSN: | 1554-8937 |
| Popis: | Among the four bioactive cationic homo-poly(amino acids) discovered in nature, two are mirror-image isomers of poly(2,4-diaminobutyric acid) (poly-Dab) whose biosynthesis has long been unexplained. Their structural analogy plausibly suggested that they could share a common biosynthetic pathway utilizing e-poly(l-lysine) synthetase-like enzymology but with an unprecedented process for enantiomeric inversion of polymer building blocks. To investigate this possibility, we comparatively explored the biosynthesis of poly-l-Dab and its mirror-image isomer poly-d-Dab in Streptomyces celluloflavus USE31 and Streptoalloteichus hindustanus NBRC15115, respectively, through genome mining, genetic inactivation, and heterologous expression combined with biochemical assays. While they shared the same biosynthetic pathway, the poly-d-Dab biosynthetic gene cluster additionally harbored the racemase gene. The critical finding that poly-d-Dab synthetase, in contrast to the synthetase generating the l-isomer, selectively activated d-Dab through adenylation conclusively demonstrated that free diffusible d-Dab preactivationally generated by the racemase is directly activated to be incorporated into the polymer. Our study thus represents the first demonstration of the stereoselective biosynthesis of a nonribosomal peptide governed by adenylation activity for a d-amino acid other than alanine. In silico sequence comparison between poly-Dab synthetases allowed us to identify amino acid residues potentially responsible for the discrimination of Dab enantiomers. Our results will provide significant insight not only for the future discovery of novel bioactive cationic poly(amino acids) but also for the creation of designer nonribosomal peptides with d-configuration. |
| Databáze: | OpenAIRE |
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