Résumé
Two related oncogenes, TCL1 and MTCP1, are overexpressed in certain T-cell prolymphocytic leukemias as a result of chromosomal rearrangements that involve the translocation of one T-cell receptor gene to either chromosome 14q32 or Xq28, respectively. The human oncoprotein p13^sup MTCP1^ is coded by the MTCP1 gene and its primary sequence is highly and only homologous to that of p14^sup TCL1^, the product of TCL1. These two proteins likely represent the first members of a new family of oncogenic proteins. A previous model of the three-dimensional solution structure of p13^sup MTCP1^ was determined recently using exclusively homonuclear proton two-dimensional NMR methods and, almost simultaneously, high-resolution crystal structures of p13^sup MTCP1^ and p14^sup TCL1^ appeared in the literature. In order to gain more insight into the details of the solution structure, we uniformly labeled p13^sup MTCP1^ with nitrogen-15. The refined structure benefits from 520 additional NOEs, extracted from either ^sup 15^N-edited 3D experiments or homonuclear 2D NOESY recorded at 800 MHz, and from a nearly complete set of Φ angular restraints. Measurements of ^sup 15^N spin relaxation times and heteronuclear ^sup 15^N{^sup 1^H}NOEs at two magnetic field strengths provided additional insights into the dynamics of the protein backbone. On the basis of these new results, a putative binding surface for this particular class of oncogenes is discussed.[PUBLICATION ABSTRACT]