MOLECULAR CHAPERONES

The Department of Biochemistryof Medical Faculty

Presents now

Edited by Attila Sandor

three dimensional informationone dimensional information

L. Fig.3-16, p.89

Str., Fig. 7.1, p.172

The model proteins for classic study of developing the three dimensional structure, that for folding. (Anfinsen)

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

L.Fig.4-29,p. 149

Fre

e en

ergy

Str. Fig. 3.57, p. 6+8

(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.

Role of chaperones in the thermodynamic point of view

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

Chaperonins

Heat shock proteins 70( Hsp70)

NucloplasminNucleoplasminS

chaperonin 60, groELchaperonin 60, groELchaperonin 10, groES(mitochondrial, bacterial)may use ATP

Heat shock proteins 90 (Hsp90)

Ellis R.J., Annu. Rev. Biochem., 1991

DNA + Histone aggregate

DNA+ Nucleoplasmin + Histone Nucleosoma (DNA + Histone)

Nucleoplasmin

Role of nucleoplasmines: assably of chromatin

Author`s picture

Representative members of the Chaperone family

Nucleoplasmins

Chaperonins

Heat shock proteins 70( Hsp70)

NucloplasminNucleoplasminS

chaperonin 60, groELchaperonin 60, groELchaperonin 10, groES(mitochondrial, bacterial)may use ATP

Heat shock proteins 90 (Hsp90)

Ellis R.J., Annu. Rev. Biochem., 1991

Rubisco denaturated with guanine at +10o C

RUBISCO and the chaperonins

Rubisco denaturated with guanine at +25o Cand chaperonin 60, chaperonin 10, ATP, Mg++ were added

When removing guanine

very poor recovery

80% recovery

Rubisco denaturated with guanine at +25o C

good recovery

Rubisco: ribulose 1,5-bisphosphate carboxylase-oxygenase

Author`s slide

L.Fig.41-31, p.152

THANK YOU FOR YOUR ATTENTION

The honored audience has the opportunity now to

download

the pictures of this lecture

Attila Sandor

c:\sandor\chaperon.ppt