2024-03-28T19:36:28Zhttp://digital.csic.es/dspace-oai/requestoai:digital.csic.es:10261/104012019-11-14T10:22:59Zcom_10261_80com_10261_1col_10261_333
DIGITAL.CSIC
author
Feio, Maria J.
author
Navarro, José A.
author
Teixeira, Miguel S.
author
Harrison, David
author
Karlsson, B. Göran
author
Rosa, Miguel A. de la
2009-02-06T13:33:29Z
2009-02-06T13:33:29Z
2004-10-29
Biochemistry 43(46): 14784-14791 (2004)
0006-2960
http://hdl.handle.net/10261/10401
10.1021/bi048655q
The thermal unfolding of the plastocyanin from Phormidium laminosum, a thermophilic
cyanobacterium, is herein described. The main objective of this work is to identify structural factors responsible for the higher stability observed in proteins from thermophilic organisms. With the aid of fluorescence spectroscopy, EPR, and NMR, the factors influencing the unfolding process of the protein
were investigated, and procedures for its study have been standardized. The different spectroscopic techniques used provided consistent results showing that the thermal unfolding of plastocyanin is irreversible under all the conditions investigated and that this irreversibility does not appear to be related to the presence of oxygen. The oxidized plastocyanin species has proven to be more stable than the reduced one, with respect to both the required temperature for protein unfolding (up to a 9°C difference between the two
forms) and the kinetics of the process. The behavior of this plastocyanin contrasts with that of other cupredoxins whose unfolding had previously been studied. The unfolding pH dependence and kinetic studies indicate a process with a tight control around the physiological pH in which plastocyanin plays its
redox role and the protein’s isoelectric point (5.2), suggesting a close compromise between function and stability.
eng
closedAccess
A thermal unfolding study of plastocyanin from the thermophilic cyanobacterium Phormidium laminosum
artículo
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