5f4b

Structure of B. abortus WrbA-related protein A (WrpA)

spinqualitylabelsall models 5f4b, resolution 2.50Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 5f4b is a 2 chain structure with sequence from Brua2. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: CL, FMN Gene: BAB1_1070 (BRUA2) Activity: NAD(P)H dehydrogenase (quinone), with EC number 1.6.5.2 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Publication Abstract from PubMed The general stress response (GSR) system of the intracellular pathogen Brucella abortus controls transcription of approximately 100 genes in response to a range of stress cues. The core genetic regulatory components of the GSR are required for B. abortus survival under non-optimal growth conditions in vitro, and for maintenance of chronic infection in an in vivo mouse model. The functions of the majority of the genes in the GSR transcriptional regulon remain undefined. bab1_1070 is among the most highly regulated genes in this regulon: its transcription is activated 20-30 fold by the GSR system under oxidative conditions in vitro. We have solved crystal structures of Bab1_1070 and demonstrate that it forms a homotetrameric complex that resembles WrbA-type NADH:quinone oxidoreductases, which are members of the flavodoxin protein family. However, B. abortus WrbA-related protein (WrpA) does not bind flavin cofactors with high affinity and does not function as an NADH:quinone oxidoreductase in vitro. Soaking crystals with flavin mononucleotide (FMN) revealed a likely low-affinity binding site adjacent to the canonical WrbA flavin binding site. Deletion of wrpA (DeltawrpA) does not compromise cell survival under acute oxidative stress in vitro or attenuate infection in cell-based or mouse models. However, a DeltawrpA strain does elicit increased splenomegaly in a mouse model suggesting that WrpA modulates B. abortus interaction with its mammalian host. Despite high structural homology with canonical WrbA proteins, we propose that B. abortus WrpA represents a functionally-distinct member of the diverse flavodoxin family. IMPORTANCE: Brucella abortus is an etiological agent of brucellosis, which is among the most common zoonotic diseases worldwide. The general stress response (GSR) regulatory system of B. abortus controls transcription of approximately 100 genes and is required for maintenance of chronic infection in a murine model; the majority of GSR-regulated genes remain uncharacterized. We present in vitro and in vivo functional and structural analyses of WrpA, whose expression is strongly induced by GSR under oxidative conditions. Though WrpA is structurally related to NADH:quinone oxidoreductases, it does not bind redox cofactors in solution, nor does it exhibit oxidoreductase activity in vitro. However, WrpA does affect spleen inflammation in a murine infection model. Our data provide evidence that WrpA forms a new functional class of WrbA/flavodoxin-family proteins. WrpA is an atypical flavodoxin-family protein under regulatory control of the Brucella abortus general stress response system.,Herrou J, Czyz DM, Willett JW, Kim HS, Chhor G, Babnigg G, Kim Y, Crosson S J Bacteriol. 2016 Feb 8. pii: JB.00982-15. PMID:26858101 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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