RELEASE OF CONTENT THROUGH MECHANO- SENSITIVE GATES IN PRESSURISED LIPOSOMES Martti Louhivuori University of Groningen M. Louhivuori / ISSP workshop / Tokyo, 24.8.2010
www.cgmartini.nl M ARTINI coarse-grained model M. Louhivuori / ISSP workshop / Tokyo, 24.8.2010
DPPC cholesterol peptide � ALYWK � Qo Qa water C1 SP1 C5 SP1 SC3 Na P4 SNd SC4 SC1 butane C1 C1 SC4 Qd C3 SC4 No M ARTINI CG model interaction sites M. Louhivuori / ISSP workshop / Tokyo, 24.8.2010
parametrisation of M ARTINI experimental � thermodynamic � data � non � bonded interactions atomistic MD simulations � bonded interactions M. Louhivuori / ISSP workshop / Tokyo, 24.8.2010
distribution angle parametrisation bonded interactions M. Louhivuori / ISSP workshop / Tokyo, 24.8.2010
parametrisation non � bonded interactions M. Louhivuori / ISSP workshop / Tokyo, 24.8.2010
THE VALIDATION THE VALIDATION comparing to experimental measurements Rhombohedral phase (experimentally observed for DOPC/DOPE 3:1 and 2:1 Lyan & Huang, 2002) side view top view Reproduced in CG simulation (Marrink & Mark, Biophys. J., 2004) M. Louhivuori / ISSP workshop / Tokyo, 24.8.2010
bilayers rafts vesicles sugars vesicles w/ proteins membrane proteins M. Louhivuori / ISSP workshop / Tokyo, 24.8.2010
bilayers rafts vesicles sugars vesicles w/ proteins membrane proteins M. Louhivuori / ISSP workshop / Tokyo, 24.8.2010
DPPC cholesterol peptide � ALYWK � SPEED GENERAL Qo Qa water C1 short � range interactions consistent modeling SP1 C5 large time � step biomolecular systems SP1 few degrees of freedom easily extended SC3 Na P4 SNd SC4 SC1 butane EASE of USE ACCURACY building � block approach parametrisation based on C1 C1 SC4 Qd limited # of particles thermodynamic data C3 physical units multi � level optimisation SC4 No M ARTINI CG model interaction sites M. Louhivuori / ISSP workshop / Tokyo, 24.8.2010
mmm! ouch! drugs patient targeted drug release. how? M. Louhivuori / ISSP workshop / Tokyo, 24.8.2010
drug delivery vehicle “nanobot” BOOM M. Louhivuori / ISSP workshop / Tokyo, 24.8.2010
drug delivery vehicle “nanobot” M. Louhivuori / ISSP workshop / Tokyo, 24.8.2010
mechano-sensitive channels “safety valves” of cell sense tension in the membrane MscL, MscK, MscS, MscM < 10 mN/m PDB: 2VV5 M. Louhivuori / ISSP workshop / Tokyo, 24.8.2010
top bottom MscL controllable activation & non � selective conductance M. Louhivuori / ISSP workshop / Tokyo, 24.8.2010
MscL activity flickering conductivity multiple levels � subconductive states activation < 1 ms de � activation 1 � 100 ms Sukharev et al. � 1997 � Annu Rev Physiol 59: 633 � 657 M. Louhivuori / ISSP workshop / Tokyo, 24.8.2010
non-selective channel no ion selectivity even small proteins pass through! 15 � 20 Å Cruickshank et al. � 1997 � Biophys J 73: 1925 � 1931 M. Louhivuori / ISSP workshop / Tokyo, 24.8.2010
photosensitivivity attached compound undergoes light induced charge separation reversible localised Koçer et al. � 2005 � Science 309: 755 � 758 M. Louhivuori / ISSP workshop / Tokyo, 24.8.2010
photosensitivivity photosensitive lipids used to transfer signal to mechanical stress reversible localised Folgering et al. � 2004 � Langmuir 20: 6985 � 6987 M. Louhivuori / ISSP workshop / Tokyo, 24.8.2010
nano-container nano-particles aka liposome aka drugs M. Louhivuori / ISSP workshop / Tokyo, 24.8.2010
nano-transporter liposomes tiny lipid vesicles membrane fusion trans � membrane transport drug delivery curvature e � ects MscL mechano � sensitive pressure valves of cells touch & hear non � selective, large membrane channel M. Louhivuori / ISSP workshop / Tokyo, 24.8.2010
game plan BOOM M. Louhivuori / ISSP workshop / Tokyo, 24.8.2010
MscL saves the day M. Louhivuori / ISSP workshop / Tokyo, 24.8.2010
660 kN/m·s � lysis oh-oh! 140 kN/m·s � ok M. Louhivuori / ISSP workshop / Tokyo, 24.8.2010
analysis M. Louhivuori / ISSP workshop / Tokyo, 24.8.2010
analysis closed open 5 us M. Louhivuori / ISSP workshop / Tokyo, 24.8.2010
activation mechanism M. Louhivuori / ISSP workshop / Tokyo, 24.8.2010
post- activation 67 mN/m � 24 nm 1.04 H2O / ns M. Louhivuori / ISSP workshop / Tokyo, 24.8.2010
140 equilibrium? tension pressure 120 tension (mN/m) / pressure (bar) 100 80 60 (-1.12 ± 0.05) bar / µs 40 (93 ± 4) µs 20 (86 ± 4) µs (-0.54 ± 0.02) mN m /µs 0 0 10 20 30 40 50 60 70 80 90 time ( µ s) M. Louhivuori / ISSP workshop / Tokyo, 24.8.2010
MFFA 3.5 RDF 3 boundary 2.5 2 1.5 potentials 1 0.5 0 0 1 2 3 4 5 6 r [nm] mimic interactions with bulk solvent 30 MFFA 20 10 0 -10 -20 Risselada et al. � 2008 � -30 2 3 4 5 6 J Phys Chem B 112: 7438 � 7447 r [nm] M. Louhivuori / ISSP workshop / Tokyo, 24.8.2010
pumping water into liposomes additional mean � field potential inside the liposome start with r = 0.01 nm increase slowly for 20ns until r = 3.9 nm fill the cavity with water, relax and repeat as needed M. Louhivuori / ISSP workshop / Tokyo, 24.8.2010
water-repellant lipid tails DOPC wDOPC modified Lennard � Jones potential against NC3 NC3 NC3 water PO4 PO4 PO4 C5 wC5 GL1 GL1 GL1 GL2 GL2 GL2 epsilon 2.0 2.0 C1 C1 C1 C1 C1 C1 sigma 0.47 0.7 C2 C2 C2 C2 C2 C2 D3 D3 D3 �� σ � 6 � � 12 D3 D3 D3 � σ V ( r ) = 4 ǫ C4 C4 C4 − r r C4 C4 C4 C5 C5 wC5 C5 C5 C5 wC5 C5 M. Louhivuori / ISSP workshop / Tokyo, 24.8.2010
3D pressure fields Ollila et al. � 2009 � Phys Rev Lett, 102: 078101 divide system into a 3D grid use local virial for each volume element calculate averages P local ( r ) = 1 δ ( r − r i ) m i v i ⊗ v i + 1 � � � δ ( r − 1) dl F ij 2 V C i j i i � = j M. Louhivuori / ISSP workshop / Tokyo, 24.8.2010
flow rate Partial densities 2000 Protein R wDOPC W � R PO4 1500 � -3 ) Density (kg m 1000 500 0 0 5 10 15 20 Box (nm) M. Louhivuori / ISSP workshop / Tokyo, 24.8.2010
summary large � scale biological water flux systems accessible to CG OUT: � 6.0 ± 1.3 �� ions/ns simulations IN: � 1.7 ± 0.3 �� ions/ns MODEL: 0.2 � 40 � ions/ns release of an osmotic � Steinbacher et al. � 2007 � shock via MscL � CurrTopicsMembranes 58:1 � 24 activation achieved pore radius � 11.6 ± 0.8 � Å � MscL activation is � exp. 15 � 20 Å � indeed a last � ditch e � ort blocking of the channel to prevent lysis by the cytoplasmic helices a first step in iris � like, non � symmetric closure? opening M. Louhivuori / ISSP workshop / Tokyo, 24.8.2010
future dye molecules to directly nano � pores formed by compare our release of other molecules, e.g. nano � particles to anti � microbial peptides experimental data activation of the channel using lyso � lipids M. Louhivuori / ISSP workshop / Tokyo, 24.8.2010
Siewert � Jan Marrink Erik van der Giessen Jelger Risselada UPPSALA UNIVERSITET David van der Spoel TAMPERE UNIVERSITY OF TECHNOLOGY Samuli Ollila Ilpo V attulainen Stockholm University Erik Lindahl M. Louhivuori / ISSP workshop / Tokyo, 24.8.2010
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