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

Str. Fig. 3.54, p. 66 Scrambled

The three dimensional structure is dictated entirely by the amino acid sequence

Str., Fig1.6 p.7

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

Heat shock proteins 70 (

Hsp70)

Heat shock proteins 90

(Hsp90)

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

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

Heat shock proteins 70 (

Hsp70)

Heat shock proteins 90

(Hsp90)

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

RUBISCO and the chaperonins

When removing guanine Rubisco denaturated with guanine at +25 o C very poor recovery Rubisco denaturated with guanine at +10 o C good recovery Rubisco denaturated with guanine at +25 o and chaperonin 60, chaperonin 10, ATP, Mg ++ were added C 80% recovery Rubisco: ribulose 1,5-bisphosphate carboxylase-oxygenase Author`s slide

L.Fig.41-31, p.152

THANK YOU FOR YOUR ATTENTION

Attila Sandor The honored audience has the opportunity now to

download

the pictures of this lecture c:\sandor\chaperon.ppt