Multiple folding states and disorder of ribosomal protein SA, a membrane receptor for laminin, anticarcinogens, and pathogens.
Biochemistry
; 51(24): 4807-21, 2012 Jun 19.
Article
em En
| MEDLINE
| ID: mdl-22640394
ABSTRACT
The human ribosomal protein SA (RPSA) is a multilocus protein, present in most cellular compartments. It is a multifunctional protein, which belongs to the ribosome but is also a membrane receptor for laminin, growth factors, prion, pathogenic microorganisms, toxins, and the anticarcinogen epigallocatechin gallate. It contributes to the crossing of the blood-brain barrier by neurotropic viruses and bacteria and is used as a biomarker of metastasis. RPSA includes an N-terminal domain, which is homologous to the prokaryotic ribosomal proteins S2, and a C-terminal extension, which is conserved in vertebrates. The structure of its N-domain has been determined from crystals grown at 17 °C. The structure of its C-domain remains unknown. We produced in Escherichia coli and purified the full-length RPSA and its N- and C-domains. We characterized the folding states of these recombinant proteins mainly by methods of fluorescence and circular dichroism spectrometry, in association with quantitative analyses of their unfolding equilibria, induced with heat or urea. The necessary equations were derived from first principles. The results showed that the N-domain unfolded according to a three-state equilibrium. The monomeric intermediate was predominant at the body temperature of 37 °C. It also existed in the full-length RPSA and bound ANS, a small fluorescent molecule. The C-domain was in an intrinsically disordered state. The recombinant N- and C-domains weakly interacted together. These results indicated a high plasticity of RPSA, which could be important for its multiple cellular localizations and functional interactions.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Proteínas Ribossômicas
/
Laminina
/
Anticarcinógenos
/
Receptores de Laminina
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Dobramento de Proteína
/
Microbiologia
Tipo de estudo:
Prognostic_studies
Limite:
Animals
/
Humans
Idioma:
En
Revista:
Biochemistry
Ano de publicação:
2012
Tipo de documento:
Article
País de afiliação:
França