Atomic force microscopy (AFM) study of the oligomeric state of CYP102A1 was carried out in three different environmental conditions -liquid, air and vacuum. It was shown that usage of a standard probe with a radius of curvature of 10 nm allowed determination of the monomers-to-oligomers ratio, a z 0.5 : 0.5, in these three media, but it wasn't possible to estimate the oligomerization degree more precisely. Application of a supersharp probe with a radius of curvature of 2 nm made it possible not only to obtain data on the ratio of monomers-to-oligomers but also to obtain the approximate ratio between dimers, trimers and tetramers 0.3 : 0.1 : 0.1, but only in vacuum. Results and discussion PCS study of CYP102A1 oligomeric stateUsing PCS, it is possible to obtain the size distribution of macromolecules directly in solution. 8 In our work, this method

Desmin intermediate filaments (IFs) play an important role in maintaining the structural and functional integrity of muscle cells. They connect contractile myofibrils to plasma membrane, nuclei, and mitochondria. Disturbance of their network due to desmin mutations or deficiency leads to an infringement of myofibril organization and to a deterioration of mitochondrial distribution, morphology, and functions. The nature of the interaction of desmin IFs with mitochondria is not clear. To elucidate the possibility that desmin can directly bind to mitochondria, we have undertaken the study of their interaction in vitro. Using desmin mutant Des(Y122L) that forms unit-length filaments (ULFs) but is incapable of forming long filaments and, therefore, could be effectively separated from mitochondria by centrifugation through sucrose gradient, we probed the interaction of recombinant human desmin with mitochondria isolated from rat liver. Our data show that desmin can directly bind to mitochondria, and this binding depends on its N-terminal domain. We have found that mitochondrial cysteine protease can disrupt this interaction by cleavage of desmin at its N-terminus.

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