The Department of Biochemistry
of Medical Faculty
Presents now
MOLECULAR CHAPERONES
Edited by Attila Sandor
one dimensional information
L. Fig.3-16, p.89
three dimensional information
The model proteins for classic study of developing the
three dimensional structure, that for folding. (Anfinsen)
Str., Fig. 7.1, p.172
Str. Fig. 3.53, p. 65
Scrambled
Str. Fig. 3.54, p. 66
The three dimensional structure is dictated
entirely by the amino acid sequence
Str., Fig1.6 p.7
Free energy
L.Fig.4-29,p. 149
Str. Fig. 3.57, p. 6+8
Role of chaperones in the thermodynamic point of view
(a) The folding of the unfolded protein (U) to the correct (C) form is favored thermodynamically.
Chaperone is not necessary.
(b) The folding of the unfolded protein (U) to the incorrect (I) form is favored thermodynamically.
Chaperone is necessary.
Ellis R.J., Annu. Rev. Biochem., 1991
The idea of molecular chaperones
Named after the human chaperone: “usually an elderly woman who
accompanies a young unmarried lady to prevent not proper interactions
with other people.
Molecular chaperones: proteins assisting folding of nascent polypeptides,
by preventing wrong folding.
Molecular chaperones catalyze the formation of correctly folded,
functionally active, native proteins, but they are not part of the product.
Expression of many chaperon is induced by stress, such as by heat, because during
heat-stress the probability of wrong folding is higher, therefore cells need more protection.
These chaperons are called heat shock proteins (HSP’s).
Author`s slide
Representative members of the Chaperone family
Nucleoplasmins
Nucloplasmin
NucleoplasminS
Chaperonins
chaperonin 60, groEL
chaperonin 60, groEL
chaperonin 10, groES
(mitochondrial, bacterial)
may use ATP
Ellis R.J., Annu. Rev. Biochem., 1991
Heat shock proteins 70
( Hsp70)
Heat shock proteins 90
(Hsp90)
Role of nucleoplasmines: assably of chromatin
DNA + Histone
DNA+ Nucleoplasmin + Histone
aggregate
Nucleosoma (DNA + Histone)
Nucleoplasmin
Author`s picture
Representative members of the Chaperone family
Nucleoplasmins
Nucloplasmin
NucleoplasminS
Chaperonins
chaperonin 60, groEL
chaperonin 60, groEL
chaperonin 10, groES
(mitochondrial, bacterial)
may use ATP
Ellis R.J., Annu. Rev. Biochem., 1991
Heat shock proteins 70
( Hsp70)
Heat shock proteins 90
(Hsp90)
RUBISCO and the chaperonins
When removing guanine
o
Rubisco denaturated with guanine at +25 C very poor recovery
o
Rubisco denaturated with guanine at +10 C
good recovery
o
Rubisco denaturated with guanine at +25 C
and chaperonin 60, chaperonin 10,
ATP, Mg++ were added
Rubisco: ribulose 1,5-bisphosphate carboxylase-oxygenase
Author`s slide
80% recovery
L.Fig.41-31, p.152
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Attila Sandor