- A: a+b two layers
- X: MoeA-I/Ornithine decarboxylase-C/Reverse ferredoxin-like domain in RNA-polymerase
- H: MoeA-I/Ornithine decarboxylase-C/Reverse ferredoxin-like domain in RNA-polymerase
- T: MoeA-I/Ornithine decarboxylase-C/Reverse ferredoxin-like domain in RNA-polymerase
- F: