LOCALIZED EXCITATIONS INDUCED IN BIOLOGICAL

MACROMOLECULES BY HIGH DENSITY PHOTONS

Suggestions for a novel concept- Biological Optical Matter

S. COMOROSAN, S. POLOSAN, M. APOSTOL

ASK NOT WHAT ASK NOT WHAT PHYSICS CAN DO FOR PHYSICS CAN DO FOR BIOLOGY, ASK WHAT BIOLOGY, ASK WHAT

BIOLOGY CAN DO FOR BIOLOGY CAN DO FOR PHYSICS.PHYSICS.

P. HänggiP. Hänggi

A possible suggestion:A possible suggestion:

BIOLOGICAL BIOLOGICAL SPECTROSCOPYSPECTROSCOPY

S. ComorosanS. Comorosan

OUTLINE:

a) Local polypeptide geometry- structural changes under high density photons (HDP) (=514 nm)

- Optical spectroscopy

- Circular dichroism- ellipticity estimation

b) Enzyme activity- SOD and CAT mechanisms

- Alterations under strong oxidative effects

- Preservation of activity under HDP

c) Theoretical considerations

Light interactions in biological systems :

• UV – oxidative effects - molecules photoionization, free radicals discharge, local disruption of

large molecules aggregations.• Visible light – weakly absorbed –

may induce local matter polarization.

In this context:Irradiation of complex biological structures

with high density green photons may induce electric dipoles by polarization effects.

The induced dipoles interact with external electromagnetic field (optical forces) and with one another, leading to organized material structures like molecular aggregates, micro-particles, etc. known in physics as “OPTICAL MATTER”.

Bovine Serum Albumine

For ultraviolet transitions

n* (220 nm)* (209 nm)

Irradiation =514 nmLight irradiation intensity 104-105 Lx

Optical spectroscopy- absorption and fluorescence spectra

0

0.05

0.10

0.15

240 280 320 360 400

ControlUVGL+UV

wavelength (nm)

Abs

orba

nce

BSA absorption spectra

0

0.5

1.0

1.5

2.0

2.5

290 330 370 410 450 490

ControlUVGL+UV

wavelength (nm)

Inte

nsity

(a.

u.)

BSA fluorescence excited at 280 nm

Obs:- uv irradiation strongly modifies the Obs:- uv irradiation strongly modifies the spectra by disrupting the molecular spectra by disrupting the molecular structures, while the green light reduces structures, while the green light reduces the disrupting effectsthe disrupting effects

Structural ellipticity alterationStructural ellipticity alteration

Circular dichroism spectroscopyCircular dichroism spectroscopy

-200

-150

-100

-50

0

200 220 240 260 280 300

ControlUVGL+UV

wavelength (nm)

CD

[mde

g]

BSA circular dichroism

-10

-6

-2

2

6

10

14

190 230 270 310 350

theoreticalexperimental

*n*

wavelength (nm)C

D (

a.u.

)

Electronic Circular Dichroism

UV light induces defolding processes witch UV light induces defolding processes witch reduce the ellipticity of the macromoleculesreduce the ellipticity of the macromolecules

Green light inhibits the defolding processes Green light inhibits the defolding processes preserving native helical structurespreserving native helical structures

Mean residual ellipticity estimations

)(deg][

12

dmolcmSAlr

MRE

100[%]100

o

oMREhelix

- measured circular dichroism (in milidegree)r – number of aninoacids residues[SA]- serum albumine concentration

Loss of -helix contents

UV denaturation 2.25%

GL irradiation 1.65%

Enzyme activity- SOD and CAT mechanisms

UV irradiation disrupts the enzyme macromolecular UV irradiation disrupts the enzyme macromolecular structure inhibiting its biological activitystructure inhibiting its biological activity

Green light preserves the native structure Green light preserves the native structure maintaining its biological activity at normal levelsmaintaining its biological activity at normal levels

Physico-chemical mechanism of GL-irradiationHOMOHOMO

LUMOLUMOUnder GL Under GL

Obs: the active center of the enzyme is Obs: the active center of the enzyme is located at the L-Histidine levellocated at the L-Histidine level

Polarization changes under green lightPolarization changes under green light

Theoretical considerations:Under light with the frequency and electric field

E, dipoles p=E are induced interacting with one another, involving an interaction energy:

}cos

])(

3[sin

])(

3[cos

])(

[{2 32

22

22

22

2

222

2

R

R

R

ERE

R

R

R

ERE

R

R

R

EREU

==ωω/c/c

when when R»1, the interaction energy becomesR»1, the interaction energy becomes::

R

RE

R

R

R

EREU

cos

)cos1(2

)cos(]

)([

222

22

2

222

2

where where is the angle interaction between is the angle interaction between E E and and RR

This is a long range interaction (This is a long range interaction (1/R1/R22))

At short-distance limit, U becomes:

)1cos3(2

1]

)(3[

222

3

2

32

22

2

ERRR

EREU

which is which is short range interactionshort range interaction between two dipoles. between two dipoles.

Obs: Obs: - We may expect an ordered state occurring for We may expect an ordered state occurring for

induced dipoles with a crystalline like structure induced dipoles with a crystalline like structure - Short range interactions may lead to localized Short range interactions may lead to localized

domains of organized biological matterdomains of organized biological matter- Long range interaction disturbs the arrangement Long range interaction disturbs the arrangement

between localized domainsbetween localized domains- We term these light induced aggregates- We term these light induced aggregates-

““Biological Optical Matter”Biological Optical Matter”

GLGL

Dispersed moleculesDispersed molecules Aggregate of macromoleculesAggregate of macromolecules

Final remarks:

Light interaction with matter generates a new force, known as “optical force” leading to new material properties- “optical matter”

In biological systems, our model suggests that such optical manipulations may induce what we term “biological optical matter”

Dipolar interaction results in the lowering energy of the biological system as compared with individual molecules, generating more stable and less reactive matter.

In the biological optical matter, a series of known light interaction effects, like UV denaturation, disruption of internal chemical bonds, generation of free radical are partially inhibited.