Crystal structure of prodigiosin binding protein PgbP, a GNAT family protein, in Serratia marcescens FS14

Acetylation is a conserved modification catalyzed by acetyltransferases that play prominent roles in a large number of biological processes. Members of the general control non-repressible 5 (GCN5)-N-acetyltransferase (GNAT) protein superfamily are widespread in all kingdoms of life and are characterized by highly conserved catalytic fold, and can acetylate a wide range of substrates. Although the structures and functions of numerous eukaryotic GNATs have been identified thus far, many GNATs in microorganisms remain structurally and functionally undescribed. Here, we determined the crystal structure of the putative GCN5-N-acetyltransferase PgbP in complex with CoA in Serratia marcescens FS14. Structural analysis revealed that the PgbP dimer has two cavities, each of which binds a CoA molecule via conserved motifs of the GNAT family. In addition, the biochemical studies showed that PgbP is a prodigiosin-binding protein with high thermal stability. To our knowledge, this is the first view of GNAT binding to secondary metabolites and it is also the first report of prodigiosin binding protein. Molecular docking and mutation experiments indicated that prodigiosin binds to the substrate binding site of PgbP. The structure efunction analyses presented here broaden our understanding of the multifunctionality of GNAT family members and may infer the mechanism of the multiple biological activities of prodigiosin. (c) 2022 Elsevier Inc. All rights reserved.

Automated summary

Acetylation is a widely conserved modification catalyzed by acetyltransferases that participate in diverse biological processes. In this study, the crystal structure of the putative GCN5-N-acetyltransferase PgbP in complex with CoA was determined. The structure analysis revealed the presence of two CoA-binding cavities in the PgbP dimer. Moreover, the biochemical studies demonstrated that PgbP is a prodigiosin-binding protein with high thermal stability. This study provides new insights into the multifunctionality of GNAT family members and the biological activities of prodigiosin.