2kz8
From Proteopedia
Solution NMR structure of MqsA, a protein from E. coli, containing a Zinc finger, N-terminal and a Helix Turn-Helix C-terminal domain
Structural highlights
Function[YGIT_ECOLI] Antitoxin component of a toxin-antitoxin (TA) module. Labile antitoxin that binds to the MqsR mRNA interferase toxin and neutralizes its endoribonuclease activity. Overexpression prevents MqsR-mediated cessation of cell growth and inhibition of cell proliferation. Overexpression also increases biofilm formation, perhaps by repressing cspD.[1] [2] [3] Also acts as a transcription factor. Both MqsA and MqsRA bind to the promoter region of the mqsRA operon, inactivating (PubMed:19943910) or activating (PubMed:20105222) transcription. Alone or in complex with MqsR binds to other promoters, inducing mcbR and spy and repressing cspD among others.[4] [5] [6] Publication Abstract from PubMedThe gene ygiT (mqsA) of Escherichia coli encodes MqsA, the antitoxin of the motility quorum sensing regulator (MqsR). Both proteins are considered to form a DNA binding complex and to be involved in the formation of biofilms and persisters. We have determined the three-dimensional solution structure of MqsA by high-resolution NMR. The protein comprises a well-defined N-terminal domain with a Zn finger motif usually found in eukaryotes, and a defined C-terminal domain with a typical prokaryotic DNA binding helix-turn-helix motif. The two well-defined domains of MqsA have almost identical structure in solution and in the two published crystal structures of dimeric MqsA bound to either MqsR or DNA. However, the connection of the two domains with a flexible linker yields a large variety of possible conformations in solution, which is not reflected in the crystal structures. MqsA binds Zn with all four cysteines, a stoichiometry of 1:1 and a femtomolar affinity (K(a)>/=10(17)M(-1) at 23 degrees C, pH 7.0). Solution structure and biophysical properties of MqsA, a Zn-containing antitoxin from Escherichia coli.,Papadopoulos E, Collet JF, Vukojevic V, Billeter M, Holmgren A, Graslund A, Vlamis-Gardikas A Biochim Biophys Acta. 2012 Jul 10. PMID:22789559[7] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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