Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
10537078 | Biochimica et Biophysica Acta (BBA) - Proteins and Proteomics | 2009 | 5 Pages |
Abstract
Myofibrillar creatine kinase (CK) buffers the cellular ATP concentration during fluctuating ATP turnover in a muscle. In order to detect structural changes of the CK molecule due to bound substrates, the dynamics of free, ATP-bound, and ATPÂ +Â creatine-bound CK were examined, using steady-state and time-resolved fluorescence spectroscopy. The intrinsic tryptophan fluorescence of non-labelled CK presented the smaller fluorescence lifetime 2.38Â ns and rotation correlation time 27Â ns for the CK-ATP (in comparison with the times 2.72Â ns and 35Â ns for the free CK), and their moderate return to the longer times 2.42Â ns and 29Â ns for the CK-ATPÂ +Â creatine complex. Three conformations for the non-labelled CK were indicated also by different quenching of fluorescence by acrylamide. Data were confirmed by anisotropy experiments with CK-(FITC labelled), providing the same substrate dependence of the rotation times (34Â ns, 27Â ns and returning 30Â ns). The results indicate the existence of three conformations arranged according to the “energy minimizing principle” by ligated substrates. In this way the data implicate another essential component of physiological control at the subcellular level in the transition of the nonreactive CK-ATPÂ +Â creatine complex to the reactive enzyme molecule.
Keywords
Related Topics
Physical Sciences and Engineering
Chemistry
Analytical Chemistry
Authors
Daniela Hornikova, Petr Herman, Jiri Mejsnar, Jaroslav Vecer, Jitka Zurmanova,