Triple resonance nuclear magnetic resonance backbone assignment of the ax I Domain integrin protein

The I-domain of the ax integrin subunit binds extracellular ligands, such as iC3b, a complement factor in the innate immune system. The expression of the axb2 integrin on immune cells, such as dendritic cells, macrophages, and monocytes, suggests an in important role in the immune system. Integrin proteins are able to bind ligands when in the "open" conformation, but not and if so with limited affinity in the "closed" conformation. NMR experiments are able to probe molecular motions at the nanosecond timescale, and are thus ideal for studying the transition between the open and closed states in integrins. Here, we report the triple resonance NMR backbone assignment of the ax I-domain integrin, as a preliminary experiment for future structural and dynamic studies.