DNA Repair Enzymes/metabolism; DNA Repair; DNA-Binding Proteins/metabolism; Amino Acid Sequence; Aspartic Acid/chemistry; Aspartic Acid/genetics; Aspartic Acid/metabolism; Binding Sites/genetics; Blotting, Western; Calorimetry; Crystallography, X-Ray; DNA Repair Enzymes/chemistry; DNA Repair Enzymes/genetics; DNA-Binding Proteins/chemistry; DNA-Binding Proteins/genetics; Glutamic Acid/chemistry; Glutamic Acid/genetics; Glutamic Acid/metabolism; Humans; Methionine/chemistry; Methionine/genetics; Methionine/metabolism; Microscopy, Electron, Transmission; Models, Molecular; Molecular Sequence Data; Mutation; Peptide Fragments/chemistry; Peptide Fragments/metabolism; Peptide Fragments/ultrastructure; Phenylalanine/chemistry; Phenylalanine/genetics; Phenylalanine/metabolism; Protein Binding; Protein Multimerization; Protein Structure, Tertiary; Sequence Homology, Amino Acid