7x17 | pdb_00007x17
Structure of Pseudomonas NRPS protein, AmbB-TC bound to Ppant-L-Ala
Structural highlights
FunctionAMBB_PSEAE Involved in the biosynthesis of the antimetabolite L-2-amino-4-methoxy-trans-3-butenoic acid (AMB), a non-proteinogenic amino acid which is toxic for prokaryotes and eukaryotes (PubMed:20543073, PubMed:25814981). Adenylates L-alanine and loads it onto its peptidyl carrier domain via a thioester linkage to the phosphopanthetheine moiety. In addition, loads activated L-Ala in trans onto the second carrier domain of AmbE (PubMed:25814981). Can also activate L-Ser, Gly and D-Ala, albeit to a lower extent (PubMed:25814981). The condensation domain of AmbB probably condenses the activated L-Ala and the L-Glu loaded on AmbE to form a L-Glu-L-Ala dipeptide at the first carrier domain of AmbE (PubMed:25814981).[1] [2] Publication Abstract from PubMedNon-ribosomal peptide synthetases (NRPS) are multi-modular/domain enzymes that catalyze the synthesis of bioactive peptides. A crucial step in the process is peptide elongation accomplished by the condensation (C) domain with the aid of a peptidyl carrier or thiolation (T) domain. Here, we examined condensation reaction carried out by NRPS AmbB involved in biosynthesis of L-2-amino-4-methoxy-trans-3-butenoic acid (AMB) in P. aeruginosa. We determined crystal structures of the truncated T-C bidomain of AmbB in three forms, the apo enzyme with disordered T domain, the holo form with serine linked phosphopantetheine (Ppant) and a holo form with substrate (L-alanine) loaded onto Ppant. The two holo forms feature the T domain in a substrate-donation conformation. Mutagenesis combined with functional assays identified residues essential for the attachment of Ppant, anchoring the Ppant-L-Ala in the donor catalytic channel and the role of the conserved His953 in condensation activity. Altogether, these results provide structural insights into the condensation reaction at the donor site with a substrate-bound C domain of AmbB and lay the foundation for understanding the molecular mechanism of condensation which is crucial for AMB synthesis. Structural insights into the substrate-bound condensation domains of non-ribosomal peptide synthetase AmbB.,Chu Yuan Kee MJ, Bharath SR, Wee S, Bowler MW, Gunaratne J, Pan S, Zhang L, Song H Sci Rep. 2022 Mar 30;12(1):5353. doi: 10.1038/s41598-022-09188-8. PMID:35354859[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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