Table 3. Differences between closed, open, and inactivated conformations.

Conformation	Closed	Open	Inactivated
Pore	Closed	Open	Closed
Flexion angle (average)	–2.2°	–5.3°	–4.4°
In-plane rotation	0 (reference)	Counterclockwise	Counterclockwise
High affinity Ca2+ 900 site	Empty	Occupied	Occupied
Ca2+ bound to ACP	No	Yes	Yes
CD/CTD	Disconnected	Connected	Connected
Position of CD-C′	Down	Up/intermediate	Up
Position of CD-C′	Up	Down/intermediate	Down
EF hand/S2–S3 loop	Separated	Separated	Form two salt bridges
S6 TMD helix (4921-4928)	π	π wide-short	π narrow-long
Lipids in TMD crevice	Present	Absent	Present

TMD: transmembrane domain.