3hzi
From Proteopedia
Structure of mdt protein
Structural highlights
Function[HIPA_ECOLI] Toxic component of a toxin-antitoxin (TA) module. Autophosphorylates (Ser-150) and phosphorylates EF-Tu in vitro (on 'Thr-383'), may act on other proteins as well. The hipA7 mutation leads to increased generation of persister cells, cells that survive antibiotic treatment probably by entering into a dormant state. Wild-type cells produce persisters at a frequency of 10-6 to 10-5 whereas mutant hipA7 cells produce persisters at a frequency of 10-2. Generation of persister cells requires (p)ppGpp as cells lacking relA or relA/spoT generate fewer or no persister cells respectively compared to hipA7. Low level expression of HipA causes cell filamentation and depending on the protein level is toxic enough to reduce cell growth or even kill cells. Expression of wild-type HipA also leads to high antibiotic tolerance of the survivor cells. The toxic effect of HipA is neutralized by its cognate antitoxin HipB. With HipB acts as a corepressor for transcription of the hipBA promoter.[1] [2] [3] [4] [5] [HIPB_ECOLI] Antitoxin component of a toxin-antitoxin (TA) module. Neutralizes the toxic effect of cognate toxin HipA. Binds to operator sites with the consensus sequence 5-'TATCCN(8)GGATA-3' to repress the hipBA operon promoter. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedBacterial multidrug tolerance is largely responsible for the inability of antibiotics to eradicate infections and is caused by a small population of dormant bacteria called persisters. HipA is a critical Escherichia coli persistence factor that is normally neutralized by HipB, a transcription repressor, which also regulates hipBA expression. Here, we report multiple structures of HipA and a HipA-HipB-DNA complex. HipA has a eukaryotic serine/threonine kinase-like fold and can phosphorylate the translation factor EF-Tu, suggesting a persistence mechanism via cell stasis. The HipA-HipB-DNA structure reveals the HipB-operator binding mechanism, approximately 70 degrees DNA bending, and unexpected HipA-DNA contacts. Dimeric HipB interacts with two HipA molecules to inhibit its kinase activity through sequestration and conformational inactivation. Combined, these studies suggest mechanisms for HipA-mediated persistence and its neutralization by HipB. Molecular mechanisms of HipA-mediated multidrug tolerance and its neutralization by HipB.,Schumacher MA, Piro KM, Xu W, Hansen S, Lewis K, Brennan RG Science. 2009 Jan 16;323(5912):396-401. PMID:19150849[6] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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