Interactions of human nuclear proteins P1Mcm3 and P1Cdc46.
Eur J Biochem
; 228(2): 431-8, 1995 Mar 01.
Article
em En
| MEDLINE
| ID: mdl-7705359
ABSTRACT
Human nuclear proteins P1Mcm3 and P1Cdc46 have high sequence similarities with the corresponding yeast proteins known to be required for the initiation of genome replication. Nuclei of proliferating HeLa cells contain relatively high amounts of P1Mcm3 (about 10(6) molecules/nucleus) of which only a small fraction is bound to a nuclear structure, most probably chromatin. At 0.5 M NaCl, the structure-bound nuclear protein can be partially solubilized as a dimer composed of P1Mcm3 and the related protein P1Cdc46. However, most protein P1Mcm3 is not bound to a nuclear structure and appears in the nucleoplasm. About 10% of protein P1Mcm3 in the soluble fraction is free and uncomplexed, and the remaining P1Mcm3 forms stable complexes with protein P1Cdc46. These P1Mcm3/Cdc46 complexes occur as dimers and in high-molecular-mass complexes (approximately 500 kDa). The high-molecular-mass complexes dissociate in 0.5 M NaCl and release P1Mcm3/Cdc46 dimers. It has frequently been proposed that the Mcm proteins may function as licensing factors for genome replication. Our data imply that the active form of an Mcm protein is not a monomer, but a protein complex that includes an Mcm3/Cdc46 dimer. DNA polymerase alpha is not a component of this complex.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Proteínas Fúngicas
/
Proteínas Nucleares
/
Proteínas de Ciclo Celular
Limite:
Animals
/
Humans
Idioma:
En
Revista:
Eur J Biochem
Ano de publicação:
1995
Tipo de documento:
Article
País de afiliação:
Alemanha