Ponder & Richards Backbone-independent rotamer library J. Mol. Biol. 193, 775-791 res rotamer chi1 chi2 Frequency ARG -t -67.6 176.9 0.463 ARG tt -174.1 -178.6 0.232 ARG +t 80.0 175.6 0.098 ARG -- -67.0 -71.7 0.085 ARG t+ 178.2 69.5 0.049 ARG ++ 57.1 82.8 0.024 ARG -+ -76.9 54.2 0.024 ASN -- -68.3 -36.8 0.303 ASN t0 -177.1 1.3 0.213 ASN -+ -67.2 128.8 0.131 ASN +0 63.9 -6.8 0.115 ASN tt -174.9 -156.8 0.115 ASN ++ 63.6 53.8 0.066 ASP -0 -68.3 -25.7 0.477 ASP t0 -169.1 3.9 0.336 ASP +0 63.7 2.4 0.159 CYS - -65.2 0.606 CYS t -179.6 0.245 CYS + 63.5 0.138 GLN -t -66.7 -178.5 0.367 GLN tt -174.6 -177.7 0.211 GLN --0 -58.7 -63.8 -46.3 0.144 GLN t+0 -179.4 67.3 26.8 0.089 GLN +t 70.8 -165.6 0.067 GLN --t -51.3 -90.4 165.0 0.044 GLN t+t 167.5 70.9 174.2 0.022 GLU -t0 -69.6 -177.2 -11.4 0.272 GLU tt0 -176.2 175.4 -6.7 0.259 GLU --0 -64.6 -69.1 -33.4 0.111 GLU -+0 -55.6 77.0 25.3 0.086 GLU +t0 69.8 -179.0 6.6 0.086 GLU t+0 -173.6 70.6 14.0 0.062 GLU +-0 63.0 -80.4 16.3 0.049 HIS -- -62.8 -74.3 0.341 HIS t+ -175.2 -87.7 0.250 HIS -+ -69.8 96.1 0.159 HIS +- 67.9 -80.5 0.136 HIS t- -177.3 100.5 0.091 HIS ++ 48.0 85.9 0.023 ILE -t -60.9 168.7 0.452 ILE -- -59.6 -64.1 0.183 ILE +t 61.7 163.8 0.161 ILE tt -166.6 166.0 0.129 ILE t+ -174.8 72.1 0.032 LEU -t -64.9 176.0 0.639 LEU t+ -176.4 63.1 0.245 LEU tt -165.3 168.2 0.048 LEU ++ 44.3 60.4 0.020 LYS -t -68.9 -178.4 0.409 LYS tt -172.1 175.3 0.236 LYS -- -58.1 -74.9 0.164 LYS t+ 173.4 83.4 0.082 LYS +t 71.5 -174.3 0.036 LYS t- -175.8 -63.9 0.027 LYS -+ -104.0 74.6 0.018 MET --- -64.5 -68.5 -75.6 0.375 MET -t -78.3 -174.7 0.250 MET tt 178.9 179.0 0.188 PHE -9 -66.3 94.3 0.463 PHE t9 -179.2 78.9 0.250 PHE +9 66.0 90.7 0.213 PHE -0 -71.9 -0.4 0.063 PRO + 26.9 -29.4 0.394 PRO - -21.8 31.2 0.349 PRO 0 0.3 -0.8 0.234 SER + 64.7 0.480 SER - -69.7 0.286 SER t -176.1 0.235 THR + 62.7 0.479 THR - -59.7 0.450 THR t -169.5 0.047 TRP -+ -70.4 100.5 0.379 TRP +- 64.8 -88.9 0.207 TRP t- -177.3 -95.1 0.138 TRP t+ -179.5 87.5 0.103 TRP -- -73.3 -87.7 0.069 TRP ++ 62.2 112.5 0.034 TYR -9 -66.5 96.6 0.486 TYR t9 -179.7 71.9 0.327 TYR +9 63.3 89.1 0.150 TYR -0 -67.2 -1.0 0.037 VAL t 173.5 0.671 VAL - -63.4 0.262 VAL + 69.3 0.054