The membrane bound N-terminal domain of human adenosine diphosphate ribosylation factor-1 (ARF1).

The small G protein adenosine diphosphate ribosylation factor-1 (ARF1) is activated by cell membrane binding of a self-folding N-terminal domain. We present a model of the human ARF1 N-terminal peptide in planar lipid bilayers, determined from neutron lamellar diffraction and circular dichroism data with molecular modelling. This amphipathic domain lies at a shallow membrane depth, ideal for regulation of the ARF1 bio-timer by rapid, reversible membrane binding. The helical region does not elongate upon membrane binding, leaving the connecting flexible linker region's length unchanged.