抗生素课件(英文)-Diffusion-in-nanostructures-Role-of

Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,Diffusion in nanostructures:Role of interaction potentials,Sergey M.Bezrukov,Laboratory of Physical and Structural Biology,NICHDNational Institutes of Health,together with:,V.Adrian Parsegian,Alexander M.Berezhkovskii,Philip A.Gurnev,Ekaterina M.Nestorovich,Amos B.Oppenheim,and Mathias Winterhalter,Diffusion in nanostructures:R,1,Roland Benz:,Asymmetry?Do you mean voltage-induced asymmetry?,Alf Honigmann:,Translocation or not?(A particle can leave the channel from the side it enters).,Boris Shklovskii:,It is all about linear vs.non-linear response.,Sunday,August 26,morning,between 9:00 and 10:00,Roland Benz:Alf Honigmann:Bori,2,Channel asymmetry,Maxwells demons,non-linear response,and all that,Channel asymmetry,3,Which one is more effective?,?,A teaser:,Which one is more effective?A,4,Plan of the talk:,Consider the simplest binding-site model,Show experiments on single,l,-phage docking to maltoporin,Introduce and explain the benefits of the diffusion model(e.g.resolve the teaser),Plan of the talk:Consider th,5,The simplest“binding site”model of ion channel,The simplest“binding site”mo,6,The simplest“binding site”model of ion channel,The simplest“binding site”mo,7,The simplest“binding site”model of ion channel:,The flux,The simplest“binding site”mo,8,Consider equilibrium:,Consider equilibrium:,9,Translocations vs.returns:,Translocations vs.returns:,10,Channel blocked from one side,Channel blocked from one side,11,Plan of the talk:,Consider the simplest binding-site model,Show experiments on single,l,-phage docking to maltoporin,Introduce and explain the benefits of the diffusion model(e.g.resolve the teaser),Plan of the talk:Consider th,12,A,KCl,KCl,KCl,KCl,A,60,m,Dia.Hole,Lipid Monolayer,Electrode,Water Tube,Teflon Chamber,15,Teflon Film,Constructing a lipid bilayer:,AKClKClKClKClA60 mLipid Monola,13,Native Maltoporin is a homotrimer,Each subunit is a 421 a.a.,18 stranded,b,-barrel,Loops,L4,L5,and,L6,form a complex near the extracellular channel vestibule,(,amino acid residues relevant for phage binding are shown in red,),Maltoporin:trimeric,b,-barrel,Native Maltoporin is a homotri,14,抗生素课件(英文)-Diffusion-in-nanostructures-Role-of,15,Effect of phage on the membrane containing Maltoporin trimers,Current corresponding to 10 Maltoporin trimers is reduced by phage at the,cis,-side addition,Phage addition to the,trans,-side of the membrane did not produce any significant changes in the current,Effect of phage on the membran,16,Ion conductance,is stable in the absence of maltohexaose,10 pA,Ion current and maltohexaose transport in single Maltoporin trimer,Maltohexaose molecules bind to a specific site inside the pore and transiently block ion current,150 mV,0 mV,Single block,Double block,Triple block,Unblock,Ion conductance is stable in t,17,cis-,trans-,/,+150 mV,/,0 mV,/,In the absence of maltohexaose and,l,phage Maltoporin trimer is,permanently open,Monitoring the functional properties of the single Maltoporin trimer embedded into bilayer,cis-trans-/+150 mV/0 mV/In,18,cis-,trans-,/,+150 mV,/,0 mV,/,Transmembrane,current gets,transiently blocked,when maltohexaose is applied to the,cis,-side,of the membrane,Phage was added simultaneously to the same(,cis,)side of the membrane,Monitoring the functional properties of the single Maltoporin trimer embedded into bilayer,cis-trans-/+150 mV/0 mV/Tra,19,cis-,trans-,/,+150 mV,/,0 mV,/,Docking of phage,decreases ion conductance,and,simultaneously,inhibits,maltohexaose penetration in,all the three pores,of Maltoporin,Monitoring the functional properties of the single Maltoporin trimer embedded into bilayer,cis-trans-/+150 mV/0 mV/Doc,20,cis-,trans-,/,+150 mV,/,0 mV,/,Subsequent,application of maltohexaose to the,trans,-side,produces current fluctuations,cis-trans-/+150 mV/0 mV/Sub,21,Probing the phage-bound state of Maltoporin for independence of pore blockage:,Thermodynamics,Binomial distribution probes independence of blocking events,P,k,:,probability of,k,(out of 3)blocked pores,k,:,#of blocked pores,p,:,probability of finding a single pore blocked,p,is determined by equilibrium constant,K eq,and sugar(maltohexaose)concentration(C)obtained from the same current traces,Blocking events are independent,Probing the phage-bound state,22,Phage docking introduces hierarchy in Maltoporin conductance,Phage-free Maltoporin trimer,D,1,=,D,2,=,D,3,Phage-bound Maltoporin trimer,D,1,D,2,D,3,D,3,D,2,D,1,D,3,D,2,D,1,maltohexaose,trans,-side,Phage docking introduces hiera,23,Phage introduces a new common pathway for ion fluxes in Maltoporin,Phage-free Maltoporin,Phage-bound Maltoporin,Phage introduces a formation of one common entryway,connecting the extracellular face of Maltoporin with the outer membrane solution,500 pS,Phage introduces a new common,24,Maltohexaose residence time increases upon phage binding,Maltohexaose,residence time,in Maltoporin pore(at the,trans,-si