Table 3.

A summary of Residues Hydrogen Bonds in Wild Type and Mutant (Molecule A) and Their Possible Effect on Protein Function and Structure

Disease	Residue	Patch*	MolA	Mutant	Amino Acid Charge Change	Possible Effect on Function and/or Structure of Protein
AD	Arg38	Patch B	MolA Arg38–MolB Glu27 MolA Arg38–MolA Gly105 MolA Arg38–MolA Ala60	HB with Gly105 is lost	From positive to not charged	WT: Direct contact with ssDNA; higher structure formation M: Reduced affinity to bind ssDNA; affected assembly
	Lys51	Patch A	MolA Lys51–MolA Val48	HB remain intact	From positive to negative	WT: Direct contact with ssDNA M: Reduced affinity to bind ssDNA
	Arg107	Patch B	MolA Arg107–MolB Arg28 MolA Arg107–MolD Ile138† MolA Arg107–MolA Leu140	HB with Leu140 and Ile138 is lost	From positive to not charged	WT: Direct contact with ssDNA; higher structure formation M: Reduced affinity to bind ssDNA; affected assembly
	Gly112	Adjacent to patch C	MolA Gly112–MolA Val33	HB remains intact	No change	WT: Unknown M: Unknown
AR	Arg127	Patch A	MolA Arg127–MolA Tyr119	HB remains intact	From positive to not charged	WT: Direct contact with ssDNA; higher structure formation M: Reduced affinity to bind ssDNA; affected assembly
	Ile132		MolA Ile132–MolA Ser88 MolA Ile132–MolA Arg86	HB remain intact	No change	Previous functional assays showed that mutant leads to lower thermostability of the tetramer.

^*Electropositive patch as identified by Yang at al.¹⁸ Patch A consists of Arg46, 46–52, Trp84, Arg86, 119–126 and Arg127 residues; patch B of Arg28, Arg38, Lys104, Arg107 residues; patch C of Trp65, Arg66, Lys81, Phe90, Arg91 and Lys113 residues; and patch D of Lys122 and Arg126 residues.

^†HB binding Arg107 with an Ile138 in opposing dimer is observed in tetramer using 3ULL template.

AD, autosomal dominant; AR, autosomal recessive; HB, hydrogen bond; M, mutant; MolA, molecule A; MolB, molecule B; MolC, molecule C; MolD, molecule D; ssDNA, single stranded DNA; WT, wild type.