engleski

Adenylation domain of nonribosomal peptide sythetase - the role of conserved motifs and protein-protein interactions

Nonribosomal peptide synthetases (NRPS) are modular proteins that catalyze the synthesis of small peptides with antibiotic, immunosuppressant, and anticancer activities, as well as siderophores. NRPS usually contain one module for each amino acid incorporated into the final peptide. Each module consists of several catalytic domains that catalyze the activation of specific amino acids (adenylation (A) domain), covalent thioester binding (peptidyl-carrier-protein (PCP) domain), formation of peptide bond (condensation (C) domain), and optionally, various substrate modifications. A domain catalyzes the two-step reaction of ATP-driven activation of amino acid, followed by its transfer to PCP domain. Sequence alignments of A domains allowed identification of 10 ‘ core motifs’ . Most of them were assigned particular functions, thanks to crystal structures and mutagenesis. Unequivocal function for several conserved motifs has not been established so far. Recently, a significant progress in mapping protein interactions between individual NRPS domains has been achieved. However, regions important for A and PCP domain interaction were not identified. In our previous work we were studying the fidelity of substrate selection by A domain, using tyrocidine synthetase from B. brevis as a model system. Our present work is focused on investigating the role of conserved sequence motifs, especially those that are shown to adopt strikingly different conformations during the two-step catalytic reaction. We are also interested in examining A domain for putative protein-protein interaction surfaces. We hope that the result obtained in these studies will facilitate the rational design of NRPSs as a means of producing peptides with novel biological activities.

peptide synthetase; adenylation domain

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