Letter to the Editor: Backbone 1H, 15N and 13C Assignments for the Subunit a of the E. Coli ATP Synthase

The structure of the 30 KDa subunit a of the membrane component (F0) of E. coli ATP synthase is investigated in a mixture of chloroform, methanol and water, a solvent previously used for solving the structure of another integral membrane protein, subunit c. Near complete backbone chemical shift assignments were made from a set of TROSY experiments including HNCO, HNCA, HN(CA)CB, HN(CO)CACB and 4D HNCOCA and HNCACO. Secondary structure of subunit a was predicted from the backbone chemical shifts using TALOS program. The protein was found to consist of multiple elongated α-helical segments. This finding is generally consistent with previous predictions of multiple transmembrane α-helices in this polytopic protein.