Dynamic structure of membrane-anchored Arf•GTP

ADP ribosylation factors (Arfs) are N-myristoylated GTP/GDP switch proteins that have key regulatory roles in vesicle transport in eukaryotic cells. ARFs execute their roles by anchoring to membrane surfaces, where they interact with other proteins to initiate budding and maturation of transport vesicles. However, existing structures of Arf center dot GTP are limited to nonmyristoylated and truncated forms with impaired membrane binding. We report a high-resolution NMR structure for full-length myristoylated yeast (Saccharomyces cerevisiae) Arf1 in complex with a membrane mimic. The two-domain structure, in which the myristoylated N-terminal helix is separated from the C-terminal domain by a flexible linker, suggests a level of adaptability in binding modes for the myriad of proteins with which Arf interacts and allows predictions of specific lipid binding sites on some of these proteins.