4XGV

Crystal structure of Escherichia coli Flavin trafficking protein, an FMN transferase

Summary for 4XGV

• Entry DOI: 10.2210/pdb4xgv/pdb
• Related: 2O18
• Descriptor: FAD:protein FMN transferase, CALCIUM ION, SODIUM ION, ... (6 entities in total)
• Functional Keywords: flavin transferase, bimetal center, lipoprotein, transferase
• Biological source: Escherichia coli
• Total number of polymer chains: 4
• Total formula weight: 151673.97

Authors

Tomchick, D.R.,Brautigam, C.A.,Deka, R.K.,Norgard, M.V. (deposition date: 2015-01-02, release date: 2015-12-16, Last modification date: 2023-09-27)

Primary citation

Deka, R.K.,Brautigam, C.A.,Liu, W.Z.,Tomchick, D.R.,Norgard, M.V.
Molecular insights into the enzymatic diversity of flavin-trafficking protein (Ftp; formerly ApbE) in flavoprotein biogenesis in the bacterial periplasm.
Microbiologyopen, 5:21-38, 2016

PubMed Abstract: We recently reported a flavin-trafficking protein (Ftp) in the syphilis spirochete Treponema pallidum (Ftp_Tp) as the first bacterial metal-dependent FAD pyrophosphatase that hydrolyzes FAD into AMP and FMN in the periplasm. Orthologs of Ftp_Tp in other bacteria (formerly ApbE) appear to lack this hydrolytic activity; rather, they flavinylate the redox subunit, NqrC, via their metal-dependent FMN transferase activity. However, nothing has been known about the nature or mechanism of metal-dependent Ftp catalysis in either Nqr- or Rnf-redox-containing bacteria. In the current study, we identified a bimetal center in the crystal structure of Escherichia coli Ftp (Ftp_Ec) and show via mutagenesis that a single amino acid substitution converts it from an FAD-binding protein to a Mg(2+)-dependent FAD pyrophosphatase (Ftp_Tp-like). Furthermore, in the presence of protein substrates, both types of Ftps are capable of flavinylating periplasmic redox-carrying proteins (e.g., RnfG_Ec) via the metal-dependent covalent attachment of FMN. A high-resolution structure of the Ftp-mediated flavinylated protein of Shewanella oneidensis NqrC identified an essential lysine in phosphoester-threonyl-FMN bond formation in the posttranslationally modified flavoproteins. Together, these discoveries broaden our understanding of the physiological capabilities of the bacterial periplasm, and they also clarify a possible mechanism by which flavoproteins are generated.

PubMed: 26626129
DOI: 10.1002/mbo3.306

Experimental method

X-RAY DIFFRACTION (1.883 Å)