Abstract
The aTfaRel2/faRel2 operon from Coprobacillus sp. D7 encodes a bicistronic type II toxin–antitoxin (TA) module. The FaRel2 toxin is a toxic small alarmone synthetase (toxSAS) that inhibits translation through the pyrophosphorylation of uncharged tRNAs at the 3′-CCA end. The toxin is neutralized by the antitoxin ATfaRel2 through the formation of an inactive TA complex. Here, the production, biophysical analysis and crystallization of ATfaRel2 and FaRel2 as well as of the ATfaRel2–FaRel2 complex are reported. ATfaRel2 is monomeric in solution. The antitoxin crystallized in space group P21212 with unit-cell parameters a = 53.3, b = 34.2, c = 37.6 Å, and the best crystal diffracted to a resolution of 1.24 Å. Crystals of FaRel2 in complex with APCPP, a nonhydrolysable ATP analogue, belonged to space group P21, with unit-cell parameters a = 31.5, b = 60.6, c = 177.2 Å, β = 90.6°, and diffracted to 2.6 Å resolution. The ATfaRel2–FaRel2Y128F complex forms a heterotetramer in solution composed of two toxins and two antitoxins. This complex crystallized in two space groups: F4132, with unit-cell parameters a = b = c = 227.1 Å, and P212121, with unit-cell parameters a = 51.7, b = 106.2, c = 135.1 Å. The crystals diffracted to 1.98 and 2.1 Å resolution, respectively.
Funder
Fonds De La Recherche Scientifique - FNRS
European Research Council, H2020 European Research Council
Fonds Jean Brachet
Fondation Van Buuren
Vetenskapsrådet
Crafoordska Stiftelsen
Eesti Teadusagentuur
Cancerfonden
Knut och Alice Wallenbergs Stiftelse
Fonds pour la Formation à la Recherche dans l'Industrie et dans l'Agriculture
Publisher
International Union of Crystallography (IUCr)
Subject
Condensed Matter Physics,Genetics,Biochemistry,Structural Biology,Biophysics