Impact of domain interchange on conformational stability and equilibrium folding of chimeric class micro glutathione transferases.
Protein Sci
; 11(9): 2208-17, 2002 Sep.
Article
em En
| MEDLINE
| ID: mdl-12192076
ABSTRACT
Rat micro class glutathione transferases M1-1 and M2-2 are homodimers that share a 78% sequence identity but display differences in stability. M1-1 is more stable at the secondary and tertiary structural levels, whereas its quaternary structure is less stable. Each subunit in these proteins consists of two structurally distinct domains with intersubunit contacts occurring between domain 1 of one subunit and domain 2 of the other subunit. The chimeric subunit variants M(12), which has domain 1 of M1 and domain 2 of M2, and its complement M(21), were used to investigate the conformational stability of the chimeric homodimers M(12)-(12) and M(21)-(21) to determine the contribution of each domain toward stability. Exchanging entire domains between class micro GSTs is accommodated by the GST fold. Urea-induced equilibrium unfolding data indicate that whereas the class micro equilibrium unfolding mechanism (i.e., N(2) <--> 2I <--> 2U) is not altered, domain exchanges impact significantly on the conformational stability of the native dimers and monomeric folding intermediates. Data for the wild-type and chimeric proteins indicate that the order of stability for the native dimer (N(2)) is M2-2 > M(12)-(12) M1-1 approximately M(21)-(21), and that the order of stability of the monomeric intermediate (I) is M1 > M2 approximately M(12) > M(21). Interactions involving Arg 77, which is topologically conserved in GSTs, appear to play an important role in the stability of both the native dimeric and folding monomeric structures.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Conformação Proteica
/
Dobramento de Proteína
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Glutationa Transferase
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Isoenzimas
Limite:
Animals
Idioma:
En
Revista:
Protein Sci
Assunto da revista:
BIOQUIMICA
Ano de publicação:
2002
Tipo de documento:
Article
País de afiliação:
África do Sul
País de publicação:
EEUU
/
ESTADOS UNIDOS
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ESTADOS UNIDOS DA AMERICA
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EUA
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UNITED STATES
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UNITED STATES OF AMERICA
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US
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USA