This domain is found in human cytoplasmic dynein-2 proteins. Cytoplasmic dynein-2 (dynein-2) performs intraflagellar transport and is associated with human skeletal ciliopathies. Dyneins share a conserved motor domain that couples cycles of ATP hydrolysis with conformational changes to produce movement. Structural analysis reveal that the motor's ring consists of six AAA+ domains (ATPases associated with various cellular activities: AAA1-AAA6) [1]. This is the first site (out of four nucleotide binding sites in the dynein motor) where the movement depends on ATP hydrolysis [2]. When this site is nucleotide free or bound to ADP, the microtubule binding domain (MTBD) binds to the microtubule and the linker adopts the straight post-power-stroke conformation. Upon ATP binding and hydrolysis, the MTBD detaches from the microtubule and the linker is primed into the pre-power-stroke conformation. Dynein's AAA+ domains are each divided into an alpha/beta large subdomain designated with an L and and alpha small subdomains designated with an S. This is the AAA1 large (AAA1L) subdomain with the accompanying small subdomain (AAA1S). AAA1L, AAA1S and AAA2L enclose ADP.vanadate (ADP.Vi, ATP-hydrolysis transition state analogue). The AAA1L sensor-I loop, which varies in position depending on dynein's nucleotide state, swings in to contact AAA2L forming the important AAA1 nucleotide-binding site [1].

1: Structure of human cytoplasmic dynein-2 primed for its power stroke. Schmidt H, Zalyte R, Urnavicius L, Carter AP; Nature. 2015;518:435-438. PMID:25470043

2: Model for the motor component of dynein heavy chain based on homology to the AAA family of oligomeric ATPases. Mocz G, Gibbons IR; Structure. 2001;9:93-103. PMID:11250194