- A: beta duplicates or obligate multimers
- X: Single-stranded left-handed beta-helix
- H: Guanosine diphospho-D-mannose pyrophosphorylase/mannose-6-phosphate isomerase linker domain
- T: Guanosine diphospho-D-mannose pyrophosphorylase/mannose-6-phosphate isomerase linker domain
- F: ManC_GMP_beta-helix