From
Disorder to Order Transition.
Disorder
is the order of the Universe.
Order
is the rare occurrence seen only in biological systems.
But
this order has come painfully slow even in Evolution.
I
would like to go step backward and look at the Symbiosis.
Symbiosis
preceded the evolution by eons of years.
Symbiosis
did not need elaborate genetic cord (which evolution’s
prerequisite).
It
needed only meeting of two cells of common interest.
Meeting
of opposing cells and parasitism came much later.
The
sex differentiation also came much later and symbiosis is not precluded
by absence of cells.
I
want to go much further back to primordial proteins and not the
structured genetically coded protein.
Random
association of amino acids could give rise peptide cords without the
need for enzymes (again proteins).
Calcium
outside layer.
Denatured
protein layer
Protein
layer mixed with fatty acid chains.
More
fatty acids and less proteins.
Bilipid
membrane with embedded protein receptors.
Protein
can accept protein of another symbiotic cell by random association.
There
is a protein called HSP or Heat Shock Protein.
This
protien is seen in prokaryotes and eukaryotes.
HSP
probably is the result of development of resistance to heat stress
stroke in evolution of cells.
There
is another protein called CRP or C Reactive Protein that is formed in
the liver under stressful conditions.
In
other words proteins in evolution have responded not only to heat but
any stressful condition.
Protein
selection embedded in membranes was probably a prerequisite for
symbiosis long before receptor formation for specific function
(Antigen and Antibody Reactions).
Heat
shock proteins
(HSP)
are a family of proteins that are produced by cells in response to
exposure to stressful conditions. They were first described in
relation to heat shock, but are now known to also be expressed during
other stresses including exposure to cold, UV light and during wound
healing or tissue remodeling. Many members of this group perform
chaperone functions by stabilizing new proteins to ensure correct
folding or by helping to refold proteins that were damaged by the
cell stress. This increase in expression is transcriptionally
regulated. The dramatic upregulation of the heat shock proteins is a
key part of the heat shock response and is induced primarily by heat
shock factor (HSF). HSPs are found in virtually all living organisms,
from bacteria to humans.
Heat-shock
proteins are named according to their molecular weight. For example,
Hsp60, Hsp70 and Hsp90 (the most widely studied HSPs) refer to
families of heat shock proteins on the order of 60, 70 and 90
kilodaltons in size, respectively. The small 8-kilodalton protein
ubiquitin, which marks proteins for degradation, also has features of
a heat shock protein. A conserved protein binding domain of
approximately 80 amino-acid alpha crystallins are known as small heat
shock proteins (sHSP).
C-reactive
protein
(CRP)
is an annular (ring-shaped), pentameric protein found in blood
plasma, whose circulating concentrations rise in response to
inflammation. It is an acute-phase protein of hepatic origin that
increases following interleukin-6 secretion by macrophages and T
cells. Its physiological role is to bind to lysophosphatidylcholine
expressed on the surface of dead or dying cells (and some types of
bacteria) in order to activate the complement system via C1q.
CRP
is synthesized by the liver in response to factors released by
macrophages and fat cells (adipocytes). It is a member of the
pentraxin family of proteins. It is not related to C-peptide
(insulin) or protein C (blood coagulation). C-reactive protein was
the first pattern recognition receptor (PRR) to be identified.
Function
CRP binds to the phosphocholine expressed on the surface of dead or dying cells and some bacteria. This activates the complement system, promoting phagocytosis by macrophages, which clears necrotic and apoptotic cells and bacteria.This so-called acute phase response occurs as a result of increasing concentrations of IL-6, which is produced by macrophages as well as adipocytes in response to a wide range of acute and chronic inflammatory conditions such as bacterial, viral, or fungal infections; rheumatic and other inflammatory diseases; malignancy; and tissue injury and necrosis. These conditions cause release of interleukin-6 and other cytokines that trigger the synthesis of CRP and fibrinogen by the liver.
CRP binds to phosphocholine on micro-organisms. It is thought to assist in complement binding to foreign and damaged cells and enhances phagocytosis by macrophages (opsonin-mediated phagocytosis), which express a receptor for CRP. It plays a role in innate immunity as an early defence system against infections.
Amyloids are aggregates of proteins that become folded into a shape that allows many copies of that protein to stick together, forming fibrils. In the human body, amyloids have been linked to the development of various diseases. Pathogenic amyloids form when previously healthy proteins lose their normal physiological functions and form fibrous deposits in plaques around cells which can disrupt the healthy function of tissues and organs.
Such amyloids have been associated with (but not necessarily as the cause of) more than 50 human diseases, known as amyloidosis, and may play a role in some neurodegenerative disorders. Some amyloid proteins are infectious; these are called prions in which the infectious form can act as a template to convert other non-infectious proteins into infectious form. Amyloids may also have normal biological functions; for example, in the formation of fimbriae in some genera of bacteria, transmission of epigenetic traits in fungi, as well as pigment deposition and hormone release in humans.
Amyloids have been known to arise from many different proteins. These polypeptide chains generally form β-sheet structures that aggregate into long fibers; however, identical polypeptides can fold into multiple distinct amyloid conformations. The diversity of the conformations may have led to different forms of the prion diseases.
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