4ynl
From Proteopedia
Crystal structure of the hood domain of Anabaena HetR in complex with the hexapeptide ERGSGR derived from PatS
Structural highlights
Function[HETR_NOSS1] Controls heterocyst differentiation. Has both a protease and a DNA-binding activity. Binds the promoter regions of hetR, hepA and patS.[1] [PATS_NOSS1] Inhibits heterocyst differentiation. Seems to control heterocyst pattern formation through intercellular signaling mechanisms. In Anabaena filaments every 10th vegetative cell terminally differentiates into a heterocyst specialized for nitrogen fixation. Seems to inhibit the formation of adjacent heterocysts. Inhibits the DNA-binding of HetR.[2] [3] [4] Publication Abstract from PubMedThe one-dimensional pattern of heterocyst in the model cyanobacterium Anabaena sp. PCC 7120 is coordinated by the transcription factor HetR and PatS peptide. Here we report the complex structures of HetR binding to DNA, and its hood domain (HetRHood) binding to a PatS-derived hexapeptide (PatS6) at 2.80 and 2.10 A, respectively. The intertwined HetR dimer possesses a couple of novel HTH motifs, each of which consists of two canonical alpha-helices in the DNA-binding domain and an auxiliary alpha-helix from the flap domain of the neighboring subunit. Two PatS6 peptides bind to the lateral clefts of HetRHood, and trigger significant conformational changes of the flap domain, resulting in dissociation of the auxiliary alpha-helix and eventually release of HetR from the DNA major grove. These findings provide the structural insights into a prokaryotic example of Turing model. Structural insights into HetR-PatS interaction involved in cyanobacterial pattern formation.,Hu HX, Jiang YL, Zhao MX, Cai K, Liu S, Wen B, Lv P, Zhang Y, Peng J, Zhong H, Yu HM, Ren YM, Zhang Z, Tian C, Wu Q, Oliveberg M, Zhang CC, Chen Y, Zhou CZ Sci Rep. 2015 Nov 18;5:16470. doi: 10.1038/srep16470. PMID:26576507[5] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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