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Titolo:
Glucose isomerase: insights into protein engineering for increased thermostability
Autore:
Hartley, BS; Hanlon, N; Jackson, RJ; Rangarajan, M;
Indirizzi:
Univ London Imperial Coll Sci Technol & Med, Dept Biochem, London SW7 2AZ,England Univ London Imperial Coll Sci Technol & Med London England SW7 2AZ gland
Titolo Testata:
BIOCHIMICA ET BIOPHYSICA ACTA-PROTEIN STRUCTURE AND MOLECULAR ENZYMOLOGY
fascicolo: 2, volume: 1543, anno: 2000,
pagine: 294 - 335
SICI:
0167-4838(200012)1543:2<294:GIIIPE>2.0.ZU;2-I
Fonte:
ISI
Lingua:
ENG
Soggetto:
D-XYLOSE ISOMERASE; STREPTOMYCES-GRISEOFUSCUS S-41; SITE-DIRECTED MUTAGENESIS; METAL-BINDING SITES; ACTINOPLANES-MISSOURIENSIS; ESCHERICHIA-COLI; ACTIVE-SITE; CLOSTRIDIUM-THERMOSULFUROGENES; BIOCHEMICAL-CHARACTERIZATION; MOLECULAR-CLONING;
Keywords:
xylose (glucose) isomerase; catalytic mechanism; metal ion binding; subunit dissociation; protease nicking; conformational change; structural comparison; thermostability; thermoinactivation pathway; protein engineering;
Tipo documento:
Review
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
88
Recensione:
Indirizzi per estratti:
Indirizzo: Hartley, BS Univ London Imperial Coll Sci Technol & Med, Dept Biochem, London SW7 2AZ,England Univ London Imperial Coll Sci Technol & Med London England SW7 2AZ
Citazione:
B.S. Hartley et al., "Glucose isomerase: insights into protein engineering for increased thermostability", BBA-PROT ST, 1543(2), 2000, pp. 294-335

Abstract

Thermostable glucose isomerases are desirable for production of 55% fructose syrups at > 90 degreesC. Current commercial enzymes operate only at 60 degreesC to produce 45% fructose syrups. Protein engineering to construct more stable enzymes has so far been relatively unsuccessful, so this review focuses on elucidation of the thermal inactivation pathway as a future guide. The primary and tertiary structures of 11 Class 1 and 20 Class 2 enzymes are compared. Within each class the structures are almost identical and sequence differences are few. Structural differences between Class 1 and Class2 are less than previously surmised. The thermostabilities of Class 1 enzymes are essentially identical, in contrast to previous reports, but in Class 2 they vary widely. In each class, thermal inactivation proceeds via the tetrameric apoenzyme, so metal ion affinity dominates thermostability. In Class 1 enzymes, subunit dissociation is not involved, but there is an irreversible conformational change in the apoenzyme leading to a more thermostable inactive tetramer. This may be linked to reversible conformational changes in the apoenzyme at alkaline pH arising from electrostatic repulsions inthe active site, which break a buried Arg-30-Asp-299 salt bridge and bringArg-30 to the surface. There is a different salt bridge in Class 2 enzymes, which might explain their varying thermostability. Previous protein engineering results are reviewed in light of these insights. (C) 2000 Elsevier Science B.V. All rights reserved.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 29/11/20 alle ore 03:19:57