4IIL

Crystal Structure of RfuA (TP0298) of T. pallidum Bound to Riboflavin

Summary for 4IIL

• Entry DOI: 10.2210/pdb4iil/pdb
• Descriptor: Membrane lipoprotein TpN38(b), RIBOFLAVIN, SODIUM ION, ... (6 entities in total)
• Functional Keywords: periplasmic-binding protein, riboflavin transport, membrane protein
• Biological source: Treponema pallidum subsp. pallidum
• Cellular location: Cell membrane ; Lipid-anchor : Q56328
• Total number of polymer chains: 1
• Total formula weight: 39061.48

Authors

Brautigam, C.A.,Deka, R.K.,Norgard, M.V. (deposition date: 2012-12-20, release date: 2013-02-27, Last modification date: 2024-02-28)

Primary citation

Deka, R.K.,Brautigam, C.A.,Biddy, B.A.,Liu, W.Z.,Norgard, M.V.
Evidence for an ABC-type riboflavin transporter system in pathogenic spirochetes.
MBio, 4:e00615-e00612, 2013

PubMed Abstract: Bacterial transporter proteins are involved in the translocation of many essential nutrients and metabolites. However, many of these key bacterial transport systems remain to be identified, including those involved in the transport of riboflavin (vitamin B(2)). Pathogenic spirochetes lack riboflavin biosynthetic pathways, implying reliance on obtaining riboflavin from their hosts. Using structural and functional characterizations of possible ligand-binding components, we have identified an ABC-type riboflavin transport system within pathogenic spirochetes. The putative lipoprotein ligand-binding components of these systems from three different spirochetes were cloned, hyperexpressed in Escherichia coli, and purified to homogeneity. Solutions of all three of the purified recombinant proteins were bright yellow. UV-visible spectra demonstrated that these proteins were likely flavoproteins; electrospray ionization mass spectrometry and thin-layer chromatography confirmed that they contained riboflavin. A 1.3-Å crystal structure of the protein (TP0298) encoded by Treponema pallidum, the syphilis spirochete, demonstrated that the protein's fold is similar to the ligand-binding components of ABC-type transporters. The structure also revealed other salient details of the riboflavin binding site. Comparative bioinformatics analyses of spirochetal genomes, coupled with experimental validation, facilitated the discovery of this new ABC-type riboflavin transport system(s). We denote the ligand-binding component as riboflavin uptake transporter A (RfuA). Taken together, it appears that pathogenic spirochetes have evolved an ABC-type transport system (RfuABCD) for survival in their host environments, particularly that of the human host.

PubMed: 23404400
DOI: 10.1128/mBio.00615-12

Experimental method

X-RAY DIFFRACTION (1.3 Å)