| Abstract
| - We describe temperature-responsive protein pores containing single elastin-like polypeptide (ELP)loops. The ELP loops were placed within the cavity of the lumen of the α-hemolysin (αHL) pore, a heptamerof known crystal structure. The cavity is roughly spherical with a molecular surface volume of about 39 500Å3. In an applied potential, the wild-type αHL pore remained open for long periods. In contrast, the ELPloop-containing αHL pores exhibited transient current blockades, the nature of which depended on thelength and sequence of the inserted loop. Together with similar results obtained with poly(ethylene glycols)covalently attached within the cavity, the data suggest that the transient current blockades are caused byexcursions of ELP into the transmembrane β-barrel domain of the pore. Below its transition temperature,the ELP loop is fully expanded and blocks the pore completely, but reversibly. Above its transitiontemperature, the ELP is dehydrated and the structure collapses, enabling a substantial flow of ions. Potentialapplications of temperature-responsive protein pores in medical biotechnology are discussed.
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