Journal of Biomolecular NMR 28: 303–304, 2004. KLUWER/ESCOM © 2004 Kluwer Academic Publishers. Printed in the Netherlands. 303 Letter to the Editor: 1 H, 13 C and 15 N resonance assignments of the region 1463-1617 of the mouse p53 Binding Protein 1 (53BP1) Gaëlle Charier a , B´ eatrice Alpha-Bazin b , Joël Couprie a , Isabelle Callebaut c , Fr´ ed´ eric B´ erenguer b , Eric Qu´ emeneur b , Bernard Gilquin a & Sophie Zinn-Justin a,∗ a D´ epartement d’Ing´ enierie et d’Etudes des Prot´ eines, CEA SACLAY, 91191 Gif-sur-Yvette, France; b D´ epartement d’Ing´ enierie et d’Etudes des Prot´ eines, CEA VALRHO, 30207 Bagnols-sur-Ceze, France; c Syst` emes mol´ eculaires et Biologie structurale, LMCP, CNRS UMR 7590, 4 place Jussieu, 75252 Paris Cedex 05, France Received 2 July 2003; Accepted 19 August 2003 Key words: DNA damage, double-strand break, signalling pathway, TUDOR domain Biological context Human 53BP1 (p53 Binding Protein 1) was initially identified in a yeast two-hybrid screen as a protein that binds to the central DNA binding domain of the tumor suppressor p53 and that enhances p53-mediated transcriptional activation (Iwabuchi et al., 1998). This 1972 amino acids protein encompasses a BRCT tan- dem in the C-terminus region. BRCT domains are found in numerous proteins involved in DNA dam- age responses (cell cycle control, recombination and DNA repair) (Callebaut et al., 1997). 53BP1 binds p53 through its first BRCT domain and through the linker between the two BRCT domains, as shown recently by X-ray cristallography (Derbyshire et al., 2002). Several recent reports showed that 53BP1 is in- volved in DNA damage responses. In the absence of genotoxic stress, 53BP1 nuclear localization is dif- fuse. After exposure to ionizing radiations, 53BP1 is hyper-phosphorylated in an ATM-dependant pathway and is rapidly relocalized to distinct nuclear foci cor- responding to DNA double strand break sites (Rappold et al., 2001). Other proteins known to be involved in the DNA damage signalling pathway were found to colocalize with 53BP1 after irradiation. In particular phosphorylated H2AX (γ–H2AX) seems to be essen- tial for 53BP1 recruitment (Fernandez-Capetillo et al., 2002) and these two proteins were shown to interact physically (Ward et al., 2003). Furthermore it seems that the recruitment of 53BP1 to γ–H2AX nuclear foci is crucial for the phosphorylation of numerous ∗ To whom correspondence should be addressed. E-mail: szinn@cea.fr ATM substrates, including SMC1, p53 and BRCA1 (Di Tullio et al., 2002, Wang et al., 2002). The re- gion 1052–1639 of human 53BP1 was shown to be necessary and sufficient for the nuclear foci formation after IR and for the interaction with γ–H2AX (Ward et al., 2003). This region is essentially constituted of low complexity sequences. The fragment 1487–1532 is however predicted by PSI-BLAST to adopt a Tudor fold, a fold found in several RNA binding proteins (Ponting, 1997). We applied NMR techniques in order to determine the solution structure of a 155 residues domain encompassing this potential Tudor domain. Here we report the 1 H, 15 N and 13 C assignment of the 1463–1617 region of mouse 53BP1 which is 99% identical to the 1478–1632 region of human 53BP1. Methods and experiments The region 1463–1617 of mouse 53BP1 was ex- pressed in E. coli strain BL21-Gold(DE3) trans- formed with plasmid pDEST15 (Invitrogen) encod- ing the 53BP1 fragment in fusion with gluthatione- S-transferase (GST) and a TEV protease (Tobacco Etch Virus protease) cleavage site between 53BP1 and GST. The protein was purified using glutathione- agarose beads (SIGMA), once to separate the fusion protein from the other bacterial proteins, and an- other time after cleavage with the TEV protease to separate the 53BP1 fragment from GST. Uniformly labeled 15 N protein was produced in minimal medium M9 containing 1 g l −1 of ( 15 NH 4 ) 2 SO 4 (Boehringer) as the nitrogen source. Uniformly labelled 13 C/ 15 N protein was produced in a rich medium prepared