5UJD

SbnI from Staphylococcus pseudintermedius

Summary for 5UJD

• Entry DOI: 10.2210/pdb5ujd/pdb
• Related: 5UJE
• Descriptor: Siderophore biosynthesis protein SbnI, FORMIC ACID (3 entities in total)
• Functional Keywords: staphyloferrin b, heme, regulator, siderophore, gene regulation
• Biological source: Staphylococcus pseudintermedius
• Total number of polymer chains: 2
• Total formula weight: 59114.02

Authors

Murphy, M.E.P.,Verstraete, M.M. (deposition date: 2017-01-17, release date: 2018-01-24, Last modification date: 2024-10-23)

Primary citation

Verstraete, M.M.,Morales, L.D.,Kobylarz, M.J.,Loutet, S.A.,Laakso, H.A.,Pinter, T.B.,Stillman, M.J.,Heinrichs, D.E.,Murphy, M.E.P.
The heme-sensitive regulator SbnI has a bifunctional role in staphyloferrin B production by Staphylococcus aureus .
J.Biol.Chem., 294:11622-11636, 2019

PubMed Abstract: infection relies on iron acquisition from its host. takes up iron through heme uptake by the iron-responsive surface determinant (Isd) system and by the production of iron-scavenging siderophores. Staphyloferrin B (SB) is a siderophore produced by the 9-gene gene cluster for SB biosynthesis and efflux. Recently, the ninth gene product, SbnI, was determined to be a free l-serine kinase that produces phospho-l-serine (OPS), a substrate for SB biosynthesis. Previous studies have also characterized SbnI as a DNA-binding regulatory protein that senses heme to control gene expression for SB synthesis. Here, we present crystal structures at 1.9-2.1 Å resolution of a SbnI homolog from (SpSbnI) in both apo form and in complex with ADP, a product of the kinase reaction; the latter confirmed the active-site location. The structures revealed that SpSbnI forms a dimer through C-terminal domain swapping and a dimer of dimers through intermolecular disulfide formation. Heme binding had only a modest effect on SbnI enzymatic activity, suggesting that its two functions are independent and structurally distinct. We identified a heme-binding site and observed catalytic heme transfer between a heme-degrading protein of the Isd system, IsdI, and SbnI. These findings support the notion that SbnI has a bifunctional role contributing precursor OPS to SB synthesis and directly sensing heme to control expression of the locus. We propose that heme transfer from IsdI to SbnI enables to control iron source preference according to the sources available in the environment.

PubMed: 31197035
DOI: 10.1074/jbc.RA119.007757

Experimental method

X-RAY DIFFRACTION (2.1 Å)