Real-time observation of cooperative enzyme activity
in liposomes and mitochondria
Tychinsky V.P.1, Weiss D.2, Vyshenskaja T.V.3, Perevedentzeva E.V.3,
Yagushinsky L.S.3, Nikandrov S.L.1
1Moscow State Institute of Radioengineering, Electronics and Automation, 78, Vernadsky pr.
117454, Moscow, Russia;
2University of Rostock, Rostock, Germany; 3Moscow State University, Moscow, Russia
Interaction between adjacent enzyme complexes in clusters is supposed to be related to cooperative effects recorded by optical techniques. This report concerns cooperative processes in ATPase clusters built in liposome membranes. These processes are associated with macroscopic fluctuations of the optical pass at membrane surface areas measuring around 0.04 µm2. The fluctuations were quantified using dynamic phase microscopy. Position of the fluctuation region correlated with local variations of the profile height in the vicinity of a cluster. Spectral analysis of space-time fluctuation parameters during ATP stimulation revealed characteristic contrast components with frequencies in the range of F = 3-6 cps the intensity of which underwent marked changes at subwave distances (30 nm). This suggested imperfect temporal correlation of active centres inside a cluster and its heterogeneous structure. Rat liver mitochondria displayed more intensive fluctuations related to ATP stimulation. Their spectra showed characteristic dominant components with frequencies in the range of F = 2-6 cps and large (100-500 nm) correlation regions encompassing several active centres. In the absence of ATP stimulation, intensive fluctuations with reproducible contrasting spectral components in the range of F = 1-3 cps were also observed in freshly isolated granulocytes from rat cerebellum and in fibroblasts.
| LOCATION |
DATE |
TIME |
| Lecture Hall II |
Monday, April 6 |
03:10 pm |