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Titolo:
Probing stability-activity relationships in the thermophilic proteasome from Thermoplasma acidophilum by random mutagenesis
Autore:
Beadell, JS; Clark, DS;
Indirizzi:
Univ Calif Berkeley, Dept Chem Engn, Berkeley, CA 94720 USA Univ Calif Berkeley Berkeley CA USA 94720 em Engn, Berkeley, CA 94720 USA
Titolo Testata:
EXTREMOPHILES
fascicolo: 1, volume: 5, anno: 2001,
pagine: 3 - 10
SICI:
1431-0651(200102)5:1<3:PSRITT>2.0.ZU;2-X
Fonte:
ISI
Lingua:
ENG
Soggetto:
CONFORMATIONAL FLEXIBILITY; PROTEINS; PRESSURE; DEHYDROGENASE; ADAPTATION; SURFACE; ENZYME;
Keywords:
Thermoplasma acidophilum; proteasome; thermostability; high pressure; random mutagenesis;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Agriculture,Biology & Environmental Sciences
Life Sciences
Citazioni:
32
Recensione:
Indirizzi per estratti:
Indirizzo: Clark, DS Univ Calif Berkeley, Dept Chem Engn, 201 Gilman Hall, Berkeley, CA 94720 USA Univ Calif Berkeley 201 Gilman Hall Berkeley CA USA 94720 20 USA
Citazione:
J.S. Beadell e D.S. Clark, "Probing stability-activity relationships in the thermophilic proteasome from Thermoplasma acidophilum by random mutagenesis", EXTREMOPHIL, 5(1), 2001, pp. 3-10

Abstract

Structural perturbations (L65H, V12L/M27T, F35V) generated by random mutation of the beta -subunit were used to probe the relationship between stability and activity in the thermophilic proteasome from Thermoplasma acidophilum. The optimum temperature for activity of each mutant (approximate to 95 degreesC) remained unchanged; however, each mutant was significantly less stable than the wild type. Stability, therefore, is not the factor limiting high-temperature activity. Interestingly, mutation L65H drastically reducedstability without affecting specific activity over a wide temperature range, providing evidence that activity and stability can be decoupled. To investigate the nature of the flexibility introduced by mutation, stability of the proteasome was examined under pressure. The application of 10,000 psi stabilized the wild-type proteasome 3.4 fold at 97 degreesC. When inactivation temperatures were chosen such that the rate of inactivation of the mutants was similar to that of the wild type, mutants with changes at the intersubunit interfaces (L65H and V12L/M27T) were similarly stabilized. Pressure was less effective in stabilizing mutant F35V, however, in which the substitution may have introduced a new pathway for inactivation.

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Documento generato il 15/07/20 alle ore 07:04:20