Regulatory domain of HypT from Salmonella typhimurium complexed with HOCl (HOCl-bound form)Regulatory domain of HypT from Salmonella typhimurium complexed with HOCl (HOCl-bound form)

Structural highlights

5ydv is a 1 chain structure with sequence from Salmonella enterica subsp. enterica serovar Typhimurium. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:X-ray diffraction, Resolution 1.752Å
Ligands:,
Resources:FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

Q7CP75_SALTY

Publication Abstract from PubMed

Hypochlorous acid (HOCl) is generated in the immune system to kill microorganisms. In Escherichia coli, a hypochlorite-specific transcription regulator, HypT, has been characterized. HypT belongs to the LysR-type transcriptional regulator (LTTR) family that contains a DNA-binding domain (DBD) and a regulatory domain (RD). Here, we identified a hypT gene from Salmonella enterica serovar Typhimurium and determined crystal structures of the full-length HypT protein and the RD. The full-length structure reveals a type of tetrameric assembly in the LTTR family. Based on HOCl-bound and oxidation-mimicking structures, we identified a HOCl-driven methionine oxidation mechanism, in which the bound HOCl oxidizes a conserved methionine residue lining the putative ligand-binding site in the RD. Furthermore, we proposed a molecular model for the oxidized HypT, where methionine oxidation by HOCl results in a conformational change of the RD, inducing a counter rotation of the DBD dimers. Target genes that are regulated by HypT and their roles in Salmonella were also investigated. DNase I footprinting experiments revealed a DNA segment containing two pseudopalindromic motifs that are separated by approximately 100 bp, suggesting that only the oxidized structure makes a concomitant binding, forming a DNA loop. An understanding of the HypT-mediated mechanism would be helpful for controlling many pathogenic bacteria by counteracting bacterial HOCl defense mechanisms.

Structural basis for HOCl recognition and regulation mechanisms of HypT, a hypochlorite-specific transcriptional regulator.,Jo I, Kim D, No T, Hong S, Ahn J, Ryu S, Ha NC Proc Natl Acad Sci U S A. 2019 Feb 26;116(9):3740-3745. doi:, 10.1073/pnas.1811509116. Epub 2019 Feb 7. PMID:30733296[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

  1. Jo I, Kim D, No T, Hong S, Ahn J, Ryu S, Ha NC. Structural basis for HOCl recognition and regulation mechanisms of HypT, a hypochlorite-specific transcriptional regulator. Proc Natl Acad Sci U S A. 2019 Feb 26;116(9):3740-3745. doi:, 10.1073/pnas.1811509116. Epub 2019 Feb 7. PMID:30733296 doi:http://dx.doi.org/10.1073/pnas.1811509116

5ydv, resolution 1.75Å

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