The effect of ion pairs on the thermal stability of D-glyceraldehyde 3-phosphate dehydrogenase from the hyperthermophilic bacterium Thermotoga maritima.
In: Protein engineering, Jg. 7 (1994-12-01), Heft 12, S. 1471-8
Online
academicJournal
Zugriff:
D-Glyceraldehyde 3-phosphate dehydrogenase from Thermotoga maritima (TmGAPDH) is intrinsically thermostable, exhibiting a thermal transition beyond 105 degrees C. Neither the amino-acid composition nor homology modelling, based on sequence alignment and known 3-D structures of the enzyme from meso- and thermophiles, provide an explanation of the anomalous stability. Recent X-ray data suggest that an increased number of ion pairs is involved. To prove this hypothesis, a number of charged residues contributing to ion pairs in TmGAPDH, but absent in the moderately thermophilic enzyme were altered. Elimination of peripheral ion pairs (E103-K104, E261-R266) was found to be ineffective. Altering a central charge cluster (R10-D47, E314, D*186) led to a drastic decrease in coenzyme binding. As a consequence, guanidine-dependent deactivation is shifted to significantly lower guanidinium chloride (GdmCl) concentrations without altering the denaturation/dissociation profile of the wild type enzyme. Mutants in the S loop (R195D, R195D-D181K) lead to a biphasic profile in the GdmCl-dependent denaturation transition and significant destabilization; at room temperature no subunit dissociation could be observed.
Titel: |
The effect of ion pairs on the thermal stability of D-glyceraldehyde 3-phosphate dehydrogenase from the hyperthermophilic bacterium Thermotoga maritima.
|
---|---|
Autor/in / Beteiligte Person: | Tomschy, A ; Böhm, G ; Jaenicke, R |
Link: | |
Zeitschrift: | Protein engineering, Jg. 7 (1994-12-01), Heft 12, S. 1471-8 |
Veröffentlichung: | Oxford : Oxford University Press ; <i>Original Publication</i>: Oxford [Oxfordshire] ; Washington, DC : IRL Press, [c1986-c2003], 1994 |
Medientyp: | academicJournal |
ISSN: | 0269-2139 (print) |
DOI: | 10.1093/protein/7.12.1471 |
Schlagwort: |
|
Sonstiges: |
|