Table 2. Conformation of Trps at Homologous Position (Trps 68 and 157) in β- and γ-Crystallins^a.

crystallin	quenching of Trp b	PDB code	dihedral angles of Trps and distance between Trp and its close-by waters and n − 3 residue
human γD-crystallin	yesc	1HK0	Trp68: ω = 167.7°, ψ = −108.66°, φ = 18.77°, χ1 = 60.5, χ2 = 79.1; H2O137 (2.9 Å from NE1), H2O132 (2.8 Å from O=C); His65 O is ∼3.5 Å from CG
			Trp157:d ω = 171.83°, ψ = −101.27°, φ = 12.10°, χ1 = 58.4, χ2 = 86.3; H2O270 (2.9 Å from NE1), H2O263 (2.7 Å from O=C); Tyr154 O is ∼3.5 Å from CG
human γS-crystallin	yes	1HA4 (C-td)	Trp157: ω = 176.55°, ψ = −111.57°, φ = 23.87°, χ1 = 61.0, χ2 = 74.4; H2O37 (2.9 Å from NE1), H2O36 (2.7 Å from O=C); Pro154 O is ∼3.5 Å from CG
human βB1-crystallin	yes	1OKI	Trp126: ω = 170.08°, ψ = −100.10°, φ = −22.53°, χ1 = 67.7, χ2 = 65.8; H2O110 (2.8 Å from NE1); Trp123 O is ∼3.5 Å from CG
			Trp218: ω = 170.49°, ψ = −103.52°, φ = 13.71°, χ1 = 60.4, χ2 = 81.9; H2O190 (3.1 Å from NE1), H2O172 (2.9 Å from O=C); Trp215 O is ∼3.5 Å from CG
bovine γB-crystallin	−,e predicted	1AMM	Trp68: ω = 173.90°, ψ = −112.42°, φ = 15.92°, χ1 = 59.4, χ2 = 83.4; H2O229 (2.9 Å from NE1), H2O237 (2.8 Å from O=C); Tyr65 O is 3.5 Å from CG
			Trp157: ω = 175.83°, ψ = −101.18°, φ = 8.82°, χ1 = 57.9, χ2 = 87.8; H2O210 (2.9 Å from NE1), H2O226 (2.8 Å from O=C); Tyr154 O is 3.5 Å from CG
rat γE-crystallin	−	1A5D	Trp68: ω = 176.00°, ψ = −113.21°, φ = 17.53°, χ1 = 64.7, χ2 = 76.3; H2O218 (3.3 Å from NE1), H2O286 (2.8 Å from O=C); Tyr65 O is 3.3 Å from CG
			Trp157: ω = 179.52°, ψ = −107.75°, φ = 21.00°, χ1 = 59.0, χ2 = 78.0; H2O220 (3.0 Å from NE1), H2O246 (3.1 Å from O=C); Tyr154 O is 3.6 Å from CG
ciona β,γ-crystallin	−, predicted	2BV2	Trp70: ω = 168.47°, ψ = −105.76°, φ = 5.63°, χ1 = 67.9, χ2 = 82.0; H2O50 (3.1 Å from NE1), H2O37 (3.1 Å from O=C), H2O45 (2.6 Å from O=C); Pro67 O is 3.5 Å from CG

^aOnly the conformation of Trps at homologous position (Trps68 and 157) in chain A of representative β- and γ-crystallins is listed above, and that of bovine γS-crystallin, bovine γD-crystallin, bovine γE-crystallin, and bovine γF-crystallin is listed in Table 3S in Supporting Information.

^bQuenching of Trp fluorescence emission refers to the lower fluorescence intensity in the native state protein with respect to the denatured state protein.

^cThe experimental characterizations of the fluorescence emission spectrum of various crystallins can be found in refs (20),(28), and (40).

^dThe amino acid sequence number is consistent with the protein database.

^e−: experimental data of the fluorescence emission spectrum of native and unfolded state protein is unavailable.