OLIGOMERIC FORMS, FUNCTIONS AND CELLULAR LOCALIZATION OF
α-CRYSTALLIN TYPE PROTEIN FROM ACHOLEPLASMA LAIDLAWII
I. E. Vishnyakov,1 S. A. Levitskii,2 V. N. Lazarev,2 J. A. Ayala,3 V. A. Ivanov,1
E. S. Snigirevskaya,1 Ya. Yu. Komissarchik,1 S. N. Borchsenius 1, *
1 Institute of Cytology RAS, St. Petersburg, Russia,
2 Scientific Research Institute of Physical-Chemical Medicine FMBA, Moscow, Russia,
and 3 Consejo Superior de Investigaciones Cientificas, Madrid, Spain;
* e-mail: borch@mail.cytspb.rssi.ru
α-Crystallin type heat shock protein (α-HSP) IbpA from Acholeplasma laidlawii was expressed in
Escherichia coli and isolated from cell extract on Ni-sepharose column. Recombinant IbpA, like other a-HSPs, spontaneously
formed oligomeres in vitro. High resolution electron microscopy revealed regular structures with
15 nm in diameter. Evaluation of molecular mass of IbpA oligomers was performed by gel filtration. Most of
oligomers consist of 24 subunits. Recombinant IbpA prevents heat denaturation of soluble proteins in cell extract
of E. coli and displays a mild positive effect on thermotolerance of E. coli cells during severe heat shock.
We investigated a localization of IbpA in A. laidlawii cell by immunocytochemistry. We suppose that IbpA may
protect various intracellular structures from damage during heat shock.
Key words: mycoplasmas, heat shock, α-HSP, oligomers, chaperone-like function, immunocytochemistry
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