Nir Keren Institute of Life Sciences The Hebrew University Jerusalem 211216 What is life Life is a characteristic distinguishing physical entities having biological processes such as signaling and selfsustaining processes from those that do not either because such functi ID: 801003
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Slide1
Is there anything quantum in biology and if so, is it important? (The biological perspective)
Nir
Keren
Institute
of Life
Sciences
,
The Hebrew University,
Jerusalem, 21.12.16
Slide2What is life?Life is a characteristic distinguishing physical entities having biological processes, such as signaling and self-sustaining processes, from those that do not, either because such functions have ceased, or because they never had such functions and are classified as inanimate.
A current definition of
life
is that organisms maintain homeostasis, are composed of cells, undergo metabolism, can grow, adapt to their environment, respond to stimuli, and reproduce.
Slide3Fig. 1 Biological systems are organised in hierarchical structures. The continuous refinement of experimental tools permits the investigation of ever finer detail giving rise to the discovery of novel phenomena. At a certain level we expect quantum physical properties to become relevant. Whether nature has evolved to enhance them to take benefit from them (quantum enhanced efficiency) or to suppress them to avoid their detrimental effects (quantum noise) represents one of interesting open question at the heart of quantum biology. (Figure courtesy of Alipasha Vaziri.)
Published in: S.F. Huelga; M.B. Plenio;
Contemporary Physics
2013,
54, 181-207.
DOI: 10.1080/00405000.2013.829687
Copyright © 2012 Taylor & Francis
Slide4Fig. 2 Cartoon illustrating the broad line of argument in this article: following the identification of general questions, we will argue that biological systems use protein structure to adjust the properties of transport or sensory networks and, at the same time, those of the environment of these networks. Mutual tuning of these structures through evolutionary adaptation may achieve optimal performance which in turn can be explained from generalisable design principles. These design principles can lead to the formulation of novel structures and experiments to amplify and verify quantum effects. The accurate description of the interplay of structured environments and quantum dynamics especially in the non-perturbative regime requires the development of novel theoretical methods. These concepts will be discussed and shown to apply to the current three examples of quantum effects in biology, photosynthesis, avian magneto-reception and olfaction. It is the hope that these examples will be joined by many others and lead to the emergence of a new research branch, quantum biology.
Published in: S.F. Huelga; M.B. Plenio;
Contemporary Physics
2013,
54, 181-207.
DOI: 10.1080/00405000.2013.829687
Copyright © 2012 Taylor & Francis
Slide5Pyruvate (3C)
Slide6Energy in biological systems
Slide7Energy in biological systems
Photosynthesis
Slide8Joseph Priestley
Experiments and Observations on Different Kinds of Air
(1774–86)
Slide9Slide10Plants
Cyanobacteria
10
Photosynthesis takes place in chloroplasts.
Light
harvesting and electron transfer reactions
take place in the thylakoid membrane system of cyanobacteria and plant chloroplasts.Light independent reaction take place in the cytosol.
Slide11Slide12LHCII
LHCII
12
Slide1313
Plants
Cyanobacteria
Slide14650 kDa dimer:19 proteins36 Chlorophylls7 Carotenoids 1 Non heme iron2 Heme
2 Quinones
2 Pheophytines
4 Manganese
1 Calcium1 Chloride
Slide15~ 20 protein subunits per monomer. At least 99 cofactors: 35 chlorophyll a, 12 beta-carotene
,
two
pheophytin
, two plastoquinonetwo heme, one non heme Fe
2+
one bicarbonate20 lipidsThe Mn4CaO5 cluster7-8 bacteriochlorophylls Per monomer.
Slide16~ 20 protein subunits per monomer.
At least
99 cofactors:
35
chlorophyll
a
, 12 beta-carotene,two pheophytin, two plastoquinonetwo heme, one non heme Fe2+one bicarbonate20 lipidsThe Mn4CaO5 clusterImage from PDB website
Slide1770 Chlorophylls
Image from PDB website
Slide1898 Chlorophylls
Image from PDB website
Slide19126 Chlorophylls
Slide20182 Chlorophylls
Slide21602 Chlorophylls
Slide22Yossi
Slide23Thermodynamic efficiency175 kJ per quantum mole photons at 680 nm9-10 photons required to fix one CO2A total of 8400 kJ for one 6 carbon sugarBurning one 6 carbon sugar yields 2804 kJThe maximum
overall thermodynamic efficiency of photosynthesis is ~33%.
23
Slide24% Quantum efficiency
Reaction coordinates
EET to the RC 80%
Fixation into organic matter 30%
Slide25Slide26Slide27Ohad et al. 2010
Maximum
efficiency
Maximum
waste
Slide28Nir Keren (Life
sceinces
, HUJI) Leeat Bar Eyal
Yossi Paltiel (Applied physics, HUJI) Ido Eisenberg, Eyal Cohen
Herbert
van Amerongen
(Wageningen University) Yashar Ranjbar
Slide29APC
hexamer
PDB: 2VJT
PC
hexamer
PDB: 1I7Y
PhycocyaninAllophycocyanin5nm
Slide30Bar Eyal et al. BBA 2015
Slide31Slide32Slide33Slide34Effects
on
Phycobilisomes
Bar Eyal et al. BBA 2015
Hydrated
Slide35Effects
on
Phycobilisomes
Hydrated
Desiccated
Slide36Effects
on
Phycobilisomes
More on
in vivo
streak camera measurements of cyanobacteria:
Chukhutsina
et al. Sci. Rep. 2015
Slide37Effects
on
Phycobilisomes
excitation equilibration.
WET 4.9
ps
DRY 3.6 psPC hexamerPDB: 1I7Y
Phycocyanin5nm
Slide38Effects
on
Phycobilisomes
EET in PC and/or EET to
APC
660
APC hexamerPDB: 2VJTPC hexamer
PDB: 1I7YPhycocyaninAllophycocyanin5nmWET 33 psDRY 17 ps
Slide39Effects
on
Phycobilisomes
EET to APC
680
and ChlorophyllsWET 114 psDRY 64
ps
Slide40Effects
on
Phycobilisomes
Decay of
APC
660
APC680 and ChlorophyllsWET 306 psDRY 234 ps
Slide41The Eisenberg hypothesis
Energy
Wet phase
Dry phase
β
84
β
155α84
β
84
β
155
α
84
Energy band
Suggested model
Wet to dry transition
Luminescence red shift
Absorbance broadening
Life-time shortening
β155
at wet phase is antenna and quencher at dry phase
Acknowledgements:
Prof.
Yossi
Paltiel
,
HUJI
Dr.
Shira
Yochelis
, HUJI
Prof.
Nir
Keren
, HUJI
Leeat
Bar-
Eyal
,
HUJI
Prof. Noam
Adir
,
Technion
Dvir
Harris,
Technion
Dr. Yael Levi-
Kalisman
, HUJI
Prof. Martin
Plenio
,
Ulm
Dr. Felipe
Caycedo-Soler
,
Ulm