- A: alpha arrays
- X: Tetrahydrodipicolinate-N-succinlytransferase, N-terminal 3-helical domain
- H: Tetrahydrodipicolinate-N-succinlytransferase, N-terminal 3-helical domain
- T: Tetrahydrodipicolinate-N-succinlytransferase, N-terminal 3-helical domain
- F: THDPS_N_2