- A: a+b two layers
- X: Omega-3 polyunsaturated fatty acid synthase subunit PfaD N-terminal domain
- H: Omega-3 polyunsaturated fatty acid synthase subunit PfaD N-terminal domain
- T: Omega-3 polyunsaturated fatty acid synthase subunit PfaD N-terminal domain
- F: PfaD_N