Solid-State NMR Studies of Adenosine 5′-Triphosphate Freeze-Trapped in the Nucleotide Site of Na,K-ATPase



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Freeze frame: The ubiquitous ion pump, Na,K-ATPase (NKA), was discovered over half a century ago, yet atomic details of the native substrate ATP in the nucleotide site remain unavailable. Here, we use low-temperature solid-state NMR spectroscopy to detect uniformly 13C-labelled ATP bound to NKA in membrane preparations. Freeze-trapping the complex prevents ATP hydrolysis and allows the detection of specific nucleotide–enzyme contacts.