Alignment of Filamentous Proteins and Associated Molecules Through Confinement in Microchannels

A technique has been developed to study the structure and interaction of aligned filamentous proteins by confining them in surface-treated silicon microchannels. The micron-size channels induce the semiflexible biopolymers with comparable or larger persistence lengths than the channel width to naturally align parallel to the channel in solution, which facilitates structural studies by x-ray diffraction and optical imaging techniques. As a model system, we investigated the cross-linking of filamentous actin (F-actin) with the bundling protein alpha-actinin in the microchannels. Synchrotron x-ray diffraction and fluorescence microscopy were used to confirm that F-actin, when bundled in the device, conforms to the alignment of the channel geometry. Published in Applied Physics Letters, v85 n23 p5775-5777, 6 December 2004. Sponsored in part by NSF grants DMR-0203755, CTS-0103516, CTS-0404444, DMR00-80034 and NIH grant GM-59288.