The chloroplast small heat shock protein--purification and characterization of pea recombinant protein.
Protein Expr Purif
; 14(1): 87-96, 1998 Oct.
Article
en En
| MEDLINE
| ID: mdl-9758755
ABSTRACT
We report here on a procedure to obtain large amounts of a chloroplast-localized heat shock protein (HSP21) with unknown structure and function, by using an Escherichia coli expression system for the pea (Pisum sativum) protein and a purification procedure based on perfusion ion-exchange chromatography. After initial precipitation steps, the sample was applied to cation- and anion-exchange on two columns connected in sequence, which allowed rapid purification of HSP21 in one equilibration and one elution step. The purified recombinant protein had an isoelectric point of 5. 0 and appeared in assembled, oligomeric form (approximately 200 kDa) composed of 21-kDa monomers, similar to the native HSP21 protein as detected by immunoblotting in plants after heat-stress treatment. This chloroplast-localized heat shock protein belongs to a special group of small heat shock proteins (sHSPs), which share an evolutionary conserved C-terminal domain with the vertebrate eye lens alpha-crystallin. The crystallins are known from both crystallographic and spectroscopic data to be all-beta proteins. In contrast, this paper presents circular dichroism spectroscopy data which shows that the purified recombinant HSP21 oligomer has a content of more than 30% alpha-helical secondary structure.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Proteínas de Plantas
/
Cloroplastos
/
Pisum sativum
/
Proteínas de Choque Térmico
Límite:
Animals
Idioma:
En
Revista:
Protein Expr Purif
Asunto de la revista:
BIOLOGIA MOLECULAR
Año:
1998
Tipo del documento:
Article
País de afiliación:
Suecia