RESUMO
Humans have always looked to nature for design inspiration, and material design on the molecular level is no different. Here we explore how this idea applies to nanoscale biomimicry, specifically examining both recent advances and our own work on engineering lipid and polymer membrane systems with cellular processes.
Assuntos
Materiais Biocompatíveis/química , Materiais Biomiméticos/química , Nanoestruturas/química , Nanotecnologia/métodos , Actinas/química , Animais , Humanos , Lipídeos/química , Lipossomos/química , Membranas Artificiais , Microscopia Eletrônica de Transmissão , Modelos Biológicos , Modelos Químicos , Transição de Fase , Polímeros/químicaRESUMO
Connexin43 (Cx43) is the most ubiquitous gap junction protein in the human body and is essential for cell-to-cell communication in a variety of organs and organ systems. As a result, Cx43 is responsible for mediating both electrical and chemical signals, passing dissolved solutes and small signaling molecules between cells in a coordinated fashion. Here, we explore the electrophysiological properties of hemichannels formed from Cx43 and Cx43 fused to eGFP (Cx43eGFP) and their interactions in a planar lipid membrane (BLM). Unlike in vivo patch clamp experiments, Cx43 was purified and isolated from other membrane constituents allowing elucidation of individual protein responses to various electrical and chemical stimuli. Using this system, we examined hemichannel electrophysiology and the roles of several well-known gap junction blockers, namely: lanthanum, heptanol, carbenoxalone and lindane. We also observed a critical number of hemichannels required for an accelerated conductance increase, an emergent electrical signature indicative of plaque formation.
Assuntos
Conexina 43/metabolismo , Bicamadas Lipídicas/metabolismo , Animais , Antiulcerosos/farmacologia , Carbenoxolona/farmacologia , Linhagem Celular , Conexina 43/genética , Eletrofisiologia , Junções Comunicantes/efeitos dos fármacos , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Heptanol/farmacologia , Hexaclorocicloexano/farmacologia , Humanos , Inseticidas/farmacologia , Lipossomos/metabolismo , Fusão de Membrana , Ratos , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismoRESUMO
Biological pores have been used to study the transport of DNA and other molecules, but most pores have channels that allow only the movement of small molecules and single-stranded DNA and RNA. The bacteriophage phi29 DNA-packaging motor, which allows double-stranded DNA to enter the virus during maturation and exit during an infection, contains a connector protein with a channel that is between 3.6 and 6 nm wide. Here we show that a modified version of this connector protein, when reconstituted into liposomes and inserted into planar lipid bilayers, allows the translocation of double-stranded DNA. The measured conductance of a single connector channel was 4.8 nS in 1 M KCl. This engineered and membrane-adapted phage connector is expected to have applications in microelectromechanical sensing, microreactors, gene delivery, drug loading and DNA sequencing.