Over het archief
Het OWA, het open archief van het Waterbouwkundig Laboratorium heeft tot doel alle vrij toegankelijke onderzoeksresultaten van dit instituut in digitale vorm aan te bieden. Op die manier wil het de zichtbaarheid, verspreiding en gebruik van deze onderzoeksresultaten, alsook de wetenschappelijke communicatie maximaal bevorderen.
Dit archief wordt uitgebouwd en beheerd volgens de principes van de Open Access Movement, en het daaruit ontstane Open Archives Initiative.
Basisinformatie over ‘Open Access to scholarly information'.
Role of disulfide bridges in the activity and stability of a cold-active α-amylase
Siddiqui, K.S.; Poljak, A.; Guilhaus, M.; Feller, G.; D'Amico, S.; Gerday, C.; Cavicchioli, R. (2005). Role of disulfide bridges in the activity and stability of a cold-active α-amylase. J. Bacteriol. 187(17): 6206-6212. dx.doi.org/10.1128/JB.187.17.6206-6212.2005
In: Journal of Bacteriology. American Society of Microbiology: Washington DC. ISSN 0021-9193; e-ISSN 1098-5530, meer
|  |
| Auteurs | | Top |
- Siddiqui, K.S.
- Poljak, A.
- Guilhaus, M.
- Feller, G., meer
|
- D'Amico, S., meer
- Gerday, C., meer
- Cavicchioli, R.
|
|
| Abstract |
The cold-adapted α-amylase from Pseudoalteromonas haloplanktis unfolds reversibly and cooperatively according to a two-state mechanism at 30°C and unfolds reversibly and sequentially with two transitions at temperatures below 12°C. To examine the role of the four disulfide bridges in activity and conformational stability of the enzyme, the eight cysteine residues were reduced with β-mercaptoethanol or chemically modified using iodoacetamide or iodoacetic acid. Matrix-assisted laser desorption-time of flight mass spectrometry analysis confirmed that all of the cysteines were modified. The iodoacetamide-modified enzyme reversibly folded/unfolded and retained approximately one-third of its activity. Removal of all disulfide bonds resulted in stabilization of the least stable region of the enzyme (including the active site), with a concomitant decrease in activity (increase in activation enthalpy). Disulfide bond removal had a greater impact on enzyme activity than on stability (particularly the active-site region). The functional role of the disulfide bridges appears to be to prevent the active site from developing ionic interactions. Overall, the study demonstrated that none of the four disulfide bonds are important in stabilizing the native structure of enzyme, and instead, they appear to promote a localized destabilization to preserve activity. |
IMIS is ontwikkeld en wordt gehost door het VLIZ.
