Table 3.

Hydrogen bonds, buried surface area, and known amanitin mutants

Residue in yeast	Δ surface area, Å2	H-bond	Residue in human	Mutations
Val-A719	−32		Asn-A742
Leu-A722	0		Leu-A745	Mouse L745F (13)
Asn-A723	−22		Asn-A746
Arg-A726	−63	NH1 to AMA pos. 4 O 3.0 Å	Arg-A749	Mouse R749P (14) Drosophila melanogaster R741H(15)
Asp-A727	−7		Asp-A750
Phe-A755	−8		Lys-A778
Ile-A756	−48		Ile-A779	Mouse I779F (14)
Ala-A759	−7		Ser-A782
Gln-A760	−33		Gln-A783
Cys-A764	0		Val-A787	Caenorhabditis elegans C777Y(15)
Val-A765	−2		Val-A788
Gly-A766	−1		Gly-A789
Gln-A767	−34	N to AMA pos. 4 O 3.1 Å	Gln-A790
		O to AMA pos. 5 N 3.2 Å
Gln-A768	−16	OE1 to AMA pos. 3 O 2.6 Å	Gln-A791
Ser-A769	−37	N to AMA pos. 2 O 3.3 Å	Asn-A792	Mouse N792D (14)
Gly-A772	−24		Gly-A795	C. elegans G785E (15)
Lys-A773	−4		Lys-A796
Arg-A774	−2		Arg-A797
Tyr-A804	−2		Tyr-A827
His-A816	−13		His-A839
Gly-A819	−19		Gly-A842
Gly-A820	−8		Gly-A843
Glu-A822	−15	OE2 to AMA pos. 2 OD2 2.6 Å	Glu-A845
Gly-A823	−13		Gly-A846
Asp-A826	−2		Asp-A849
Thr-A1080	−1		Thr-A1103
Leu-A1081	−63		Leu-A1104
Lys-A1092	−37		Lys-A1115
Lys-A1093	−1		Asn-A1116
Gln-B763	−16		Gln-B718
Pro-B765	−11		Pro-B720
Total	−541

Δ surface area (Ų) is the change in solvent-exposed surface as calculated with program areaimol, using a standard probe radius of 1.4 Å. Potential hydrogen bonds with a donor-acceptor distance below 3.3 Å were included. Residues that are different between yeast and human are in bold. Mutations are changes in Rpb1 in eukaryotes that are known to affect α-amanitin inhibition. α-Amanitin also seems to make a contact with part of the disordered loop between A1081 and A1092. Unfortunately, only density for ∼1 amino acid appears, preventing placement of this loop or even reliable determination of which amino acid in the disordered loop is responsible for this interaction.