SMILES: C(CC(CC(=O)[O-])(C(=O)O)O)C(=O)[O-].[NH2-].[SH-].[SH-].[SH-].[SH-].[SH-].[SH-].[SH-].[SH-].[SH-].[Fe].[Fe].[Fe].[Fe].[Fe].[Fe].[Fe].[Fe]
Description: The molecule is p-cluster from Mo-independent nitrogenases, deprotonated to pH 7.3. Unfortunately, there are no structures available, and one of the O ligands of Fe has actually not been confirmed (hence the X in the name) It has a role as a cofactor.