Cell Language Theory, The: Connecting Mind And Matter

82 The Cell Language Theory: Connecting Mind and Matter

b2861 The Cell Language Theory: Connecting Mind and Matter “6x9”

(4) Another way to describe the difference between IFH and PFH is that,

in the former, L “instructs” E to change its conformation to E′, while,

in the latter, L “selects” E′ over E which are both available to L due

to the thermal fluctuations between the two conformers (or confor-

mational isomers) E and E′, thus, it can be stated that IFH is based

on instruction to assume one conformation, whereas PFH is based on

selection out of a set of thermally induced conformations.

An indirect evidence for PFH was reported by Ravindranathan [75,

173] who used X-ray crystallographic data on the ribose binding protein

(RBP) to calculate the probabilities of observing the “open” and “closed”

conformations of this protein in the absence of ribose. (RBP transports the

ribose molecule across the plasma membrane in Escherichia coli.) They

found that RBP can exist in closed and open conformations in 4 and 96%

of the time, respectively, in the absence of ribose. Most interestingly, they

found that ribose can bind only to the closed form, thereby shifting the

equilibrium toward the closed conformation. Their findings can be repre-

sented schematically as follows:

RBPopen ↔ RBPclosed, (3.13)

Ribose + RBPclosed ↔ Ribose • RBPclosed, (3.14)

Processes (3.13) and (3.14) can be accounted for by PFH (see

Process (3.11)) which is based on the GFCP or the PSFP, in terms of the

differential kinetic properties between RBP (i.e., slow conformation

change) and ribose molecules (i.e., fast diffusion in and out of the binding

pocket of RBP) secondary to their size differences, which dictate that, in

order for ribose to bind to RBP, the slower conformational changes of RBP

must precede the faster thermal motions (i.e., collisions) of ribose against

the binding site of RBP.

Many hormones and cytokines exert their biological actions on cells by

binding to their target receptors which undergo dimerization. Biologists have

been assuming that hormone/cytokine binding “induces” dimerization of

receptor monomers, R, likely influenced by the induced-fit hypothesis [28]:

R + H ↔ R•H + R ↔ R•H•R → biological actions, (3.15)

b2861_Ch-03.indd 82 17-10-2017 11:46:21 AM