New structural determinants for c-Myc specific heterodimerization with Max and development of a novel homodimeric c-Myc b-HLH-LZ.
J Mol Recognit
; 25(7): 414-26, 2012 Jul.
Article
en En
| MEDLINE
| ID: mdl-22733550
c-Myc must heterodimerize with Max to accomplish its functions as a transcription factor. This specific heterodimerization occurs through the b-HLH-LZ (basic region, helix 1-loop-helix 2-leucine zipper) domains. In fact, many studies have shown that the c-Myc b-HLH-LZ (c-Myc'SH) preferentially forms a heterodimer with the Max b-HLH-LZ (Max'SH). The primary mechanism underlying the specific heterodimerization lies on the destabilization of both homodimers and the formation of a more stable heterodimer. In this regard, it has been widely reported that c-Myc'SH has low solubility and homodimerizes poorly and that repulsions within the LZ domain account for the homodimer instability. Here, we show that replacing one residue in the basic region and one residue in Helix 1 (H(1)) of c-Myc'SH with corresponding residues conserved in b-HLH proteins confers to c-Myc'SH a higher propensity to form a stable homodimer in solution. In stark contrast to the wild-type protein, this double mutant (L362R, R367L) of the c-Myc b-HLH-LZ (c-Myc'RL) shows limited heterodimerization with Max'SH in vitro. In addition, c-Myc'RL forms highly stable and soluble complexes with canonical as well as non-canonical E-box probes. Altogether, our results demonstrate for the first time that structural determinants driving the specific heterodimerization of c-Myc and Max are embedded in the basic region and H(1) of c-Myc and that these can be exploited to engineer a novel homodimeric c-Myc b-HLH-LZ with the ability of binding the E-box sequence autonomously and with high affinity.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Proteínas Proto-Oncogénicas c-myc
/
Factores de Transcripción Básicos con Cremalleras de Leucinas y Motivos Hélice-Asa-Hélice
/
Dominios y Motivos de Interacción de Proteínas
/
Multimerización de Proteína
Tipo de estudio:
Prognostic_studies
Límite:
Animals
/
Humans
Idioma:
En
Revista:
J Mol Recognit
Asunto de la revista:
BIOLOGIA MOLECULAR
Año:
2012
Tipo del documento:
Article
País de afiliación:
Canadá
Pais de publicación:
Reino Unido