PDB ID:3CRP Metal site ID: 3CRP-NA-1 Bound amino acids or nucleotide residues: H2 Group identifier: S1 Is homomeric: True Amino acid or nucleotide residue IDs: HIS B.19 HIS C.19 All ligands IDs: HIS B.19 HIS C.19 Number of coordinating amino acids or nucleotide residues: 2 Number of coordinating ligands: 2 Number of coordinating chains: 2 Number of coordinating chains: 2