Chemoenzymatic and Template-Directed Synthesis of Bioactive Macrocyclic Peptides

Abstract

SUMMARY Non-ribosomally synthesized peptides have compelling biological activities ranging from antimicrobial to immunosuppressive and from cytostatic to antitumor. The broad spectrum of applications in modern medicine is reflected in the great structural diversity of these natural products. They contain unique building blocks, such as d-amino acids, fatty acids, sugar moieties, and heterocyclic elements, as well as halogenated, methylated, and formylated residues. In the past decades, significant progress has been made toward the understanding of the biosynthesis of these secondary metabolites by nonribosomal peptide synthetases (NRPSs) and their associated tailoring enzymes. Guided by this knowledge, researchers genetically redesigned the NRPS template to synthesize new peptide products. Moreover, chemoenzymatic strategies were developed to rationally engineer nonribosomal peptides products in order to increase or alter their bioactivities. Specifically, chemical synthesis combined with peptide cyclization mediated by nonribosomal thioesterase domains enabled the synthesis of glycosylated cyclopeptides, inhibitors of integrin receptors, peptide/polyketide hybrids, lipopeptide antibiotics, and streptogramin B antibiotics. In addition to the synthetic potential of these cyclization catalysts, which is the main focus of this review, different enzymes for tailoring of peptide scaffolds as well as the manipulation of carrier proteins with reporter-labeled coenzyme A analogs are discussed.

Identification and Characterization of the Pyridomycin Biosynthetic Gene Cluster of Streptomyces pyridomyceticus NRRL B-2517

“…Many of these natural products, such as cyclosporins, vancomycin, erythromycin, and FK506, are synthesized by multifunctional megasynthase molecular "assembly lines" (2)(3)(4)(5). There are two types of megasynthases: nonribosomal peptide synthetases (NRPSs) 2 and polyketide synthases (PKSs).…”

Search of the human proteome for endomorphin-1 and endomorphin-2 precursor proteins

“…Clearly, this proposed endomorphin de novo biosynthetic pathway requires more robust experimental support, including chemical identity of the peptides with the incorporated label. Certain bacteria and fungi are capable of synthesizing a diverse set of peptides using multienzyme complexes (the non-ribosomal peptide synthetases) and some of these peptides, for example, vancomycin, are therapeutically important (reviewed in Grunewald and Marahiel, 2006). Like carnosine, these non-ribosomally synthesized peptides generally contain building blocks in addition to the 20 common amino acids found in proteins, such as D-amino acids, N-acyl groups, methylated residues, oxidized groups, glycosylated side chains, and heterocyclic moieties.…”

Proteome-wide analysis of the functional roles of bacilysin biosynthesis in Bacillus subtilis

“…Moreover, in contrast to proteins produced by ribosomal synthesis, small peptide products contain not only the common 20 amino acids but also hundreds of different building blocks, suggesting a nonribosomal origin of biosynthesis Sieber and Marahiel, 2005;Grünewald and Marahiel, 2006).…”

“…1.1), peptide bond formation takes place on multienzymes designated as peptide synthetases, on which amino acid substrates are first activated by ATP hydrolysis to the corresponding adenylate. This unstable intermediate is subsequently transferred to another site of the multienzyme where it is bound as a thioester to the cysteamine group of an enzyme-bound 4"-phosphopantetheinyl (4"-PP) cofactor Mootz et al, 2002;Sieber and Marahiel, 2005;Grünewald and Marahiel, 2006). According to the present multiple carrier model of nonribosomal peptide synthesis, nonribosomal peptide synthetases (NRPSs) are composed of repetitive units called as modules, each about 1.000 -1.500 amino acids in length, which are capable of incorporating one amino acid constituent at a time into peptide chain Schwarzer and Marahiel, 2001;Kallow et al, 2002).…”