Low resolution structural study of two human HSP40 chaperones in solution. DJA1 from subfamily A and DJB4 from subfamily B have different quaternary structures.
J Biol Chem
; 280(14): 13671-81, 2005 Apr 08.
Article
em En
| MEDLINE
| ID: mdl-15661747
Proteins that belong to the heat shock protein (Hsp) 40 family assist Hsp70 in many cellular functions and are important for maintaining cell viability. A knowledge of the structural and functional characteristics of the Hsp40 family is therefore essential for understanding the role of the Hsp70 chaperone system in cells. In this work, we used small angle x-ray scattering and analytical ultracentrifugation to study two representatives of human Hsp40, namely, DjA1 (Hdj2/dj2/HSDJ/Rdj1) from subfamily A and DjB4 (Hlj1/DnaJW) from subfamily B, and to determine their quaternary structure. We also constructed low resolution models for the structure of DjA1-(1-332), a C-terminal-deleted mutant of DjA1 in which dimer formation is prevented. Our results, together with the current structural information of the Hsp40 C-terminal and J-domains, were used to generate models of the internal structural organization of DjA1 and DjB4. The characteristics of these models indicated that DjA1 and DjB4 were both dimers, but with substantial differences in their quaternary structures: whereas DjA1 consisted of a compact dimer in which the N and C termini of the two monomers faced each other, DjB4 formed a dimer in which only the C termini of the two monomers were in contact. The two proteins also differed in their ability to bind unfolded luciferase. Overall, our results indicate that these representatives of subfamilies A and B of human Hsp40 have different quaternary structures and chaperone functions.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Estrutura Secundária de Proteína
/
Estrutura Quaternária de Proteína
/
Proteínas de Choque Térmico
Tipo de estudo:
Prognostic_studies
Limite:
Humans
Idioma:
En
Revista:
J Biol Chem
Ano de publicação:
2005
Tipo de documento:
Article
País de afiliação:
Brasil
País de publicação:
Estados Unidos