%0 Journal Article
%A Das, Uddipan
%A Pogenberg, Vivian
%A Tiruttani Subhramanyam, Udaya Kumar
%A Matthias, Wilmanns
%A Gourinath, Samudrala
%A Srinivana, Alagiri
%T Crystal structure of the VapBC-15 complex from Mycobacterium tuberculosis reveals a two-metal ion dependent PIN-domain ribonuclease and a variable mode of toxin-antitoxin assembly
%J Journal of structural biology
%V 188
%N 3
%@ 1047-8477
%C San Diego, Calif.
%I Elsevier
%M FZJ-2014-05967
%P 249–258
%D 2014
%Z Article in press
%X Although PIN (PilT N-terminal)-domain proteins are known to have ribonuclease activity, their specific mechanism of action remains unknown. VapCs form a family of ribonucleases that possess a PIN-domain assembly and are known as toxins. The activities of VapCs are impaired by VapB antitoxins. Here we present the crystal structure of the VapBC-15 toxin–antitoxin complex from Mycobacterium tuberculosis determined to 2.1 Å resolution. The VapB-15 and VapC-15 components assemble into one heterotetramer (VapB2C2) and two heterotrimers (VapBC2) in each asymmetric unit of the crystal. The active site of VapC-15 toxin consists of a cluster of acidic amino acid residues and two divalent metal ions, forming a well organised ribonuclease active site. The distribution of the catalytic-site residues of the VapC-15 toxin is similar to that of T4 RNase H and of Methanococcus jannaschii FEN-1, providing strong evidence that these three proteins share a similar mechanism of activity. The presence of both VapB2C2 and VapBC2 emphasizes the fact that the same antitoxin can bind the toxin in 1:1 and 1:2 ratios. The crystal structure determination of the VapBC-15 complex reveals for the first time a PIN-domain ribonuclease protein that shows two metal ions at the active site and a variable mode of toxin–antitoxin assembly. The structure further shows that VapB-15 antitoxin binds to the same groove meant for the binding of putative substrate (RNA), resulting in the inhibition of VapC-15’s toxicity.
%F PUB:(DE-HGF)16
%9 Journal Article
%U <Go to ISI:>//WOS:000346229500007
%R 10.1016/j.jsb.2014.10.002
%U https://juser.fz-juelich.de/record/172498