Description: This structure provides the first structural insights into a two-subunit Trk K⁺ transporter gating ring assembly, representing an evolutionary precursor to modern single-subunit systems. The 160 kDa octameric TM1088A:TM1088B complex reveals AMP-binding at Rossmann-like folds, extensive protein interfaces burying ~18,000 Ų of surface area, and thermophilic adaptations including interfacial salt bridges.