Biology Reference
In-Depth Information
A
random interactions
between the proteins
selection of
a structure
B
C
D
E
X
stable core
D'
E'
D''
non-selected structures
(devised from Kupiec, 1999)
F
IGURE
15. Principle of ontophylogenesis. A:
The five polygons represent proteins
which are not stereospecific.
B:
They can associate with each other in different ran-
dom ways and produce several structures.
C:
These structures do not have the same
properties. In a given environment, one of them is selected because it is better
adapted.
D and E:
This structure is never totally stabilised. It is partially modified
owing to the random interactions of the proteins (D, D′, D′′, E, E′), but its central
core does not change because it is more stable (X). One of these potential struc-
tures may be selected depending on changes in the environment.
Let us imagine five proteins (Fig. 15A) capable of randomly com-
bining and giving rise to several potential structures. These struc-
tures represent a cell in different states of differentiation (Fig. 15B).
The stability and probability of each structure being formed
depends on the probabilities of molecules encountering each other
and the stability of their interactions. A single structure is selected
