Finding intermodel H-bonds Finding intramodel H-bonds Constraints relaxed by 0.4 angstroms and 20 degrees Models used: #0 7jot_A.cif H-bonds (donor, acceptor, hydrogen, D..A dist, D-H..A dist): SER 7.A N ASN 100.A OD1 no hydrogen 3.051 N/A HIS 11.A N THR 26.A OG1 no hydrogen 3.254 N/A CYS 12.A SG HIS 11.A O no hydrogen 3.913 N/A CYS 12.A SG THR 26.A O no hydrogen 3.968 N/A ASP 13.A N THR 24.A O no hydrogen 3.393 N/A SER 14.A OG ASP 78.A OD2 no hydrogen 3.530 N/A THR 15.A N ILE 22.A O no hydrogen 3.026 N/A LEU 17.A N ARG 20.A O no hydrogen 2.949 N/A ASP 19.A N ASP 19.A OD1 no hydrogen 2.486 N/A VAL 21.A N TRP 467.A O no hydrogen 3.123 N/A ILE 22.A N THR 15.A O no hydrogen 3.092 N/A THR 23.A N ILE 465.A O no hydrogen 3.002 N/A THR 24.A N ASP 13.A O no hydrogen 3.184 N/A THR 24.A OG1 GLU 464.A OE2 no hydrogen 2.551 N/A SER 25.A N VAL 463.A O no hydrogen 3.097 N/A SER 25.A OG CYS 72.A O no hydrogen 2.831 N/A THR 26.A OG1 HIS 11.A O no hydrogen 2.856 N/A ARG 27.A N VAL 461.A O no hydrogen 3.053 N/A ARG 27.A NE PRO 146.A O no hydrogen 2.980 N/A ARG 27.A NH1 THR 26.A O no hydrogen 3.206 N/A ARG 27.A NH2 PRO 146.A O no hydrogen 2.981 N/A THR 28.A OG1 GLN 460.A OE1 no hydrogen 2.756 N/A TRP 29.A N GLY 459.A O no hydrogen 3.028 N/A ALA 30.A N PHE 153.A O no hydrogen 3.197 N/A LEU 31.A N SER 457.A O no hydrogen 2.791 N/A THR 33.A OG1 GLN 455.A O no hydrogen 3.189 N/A TYR 34.A OH ILE 155.A O no hydrogen 2.580 N/A ASN 35.A ND2 LEU 38.A O no hydrogen 3.063 N/A ASN 35.A ND2 SER 59.A OG no hydrogen 2.765 N/A HIS 37.A N TYR 34.A O no hydrogen 3.206 N/A TYR 39.A OH GLU 179.A OE1 no hydrogen 2.759 N/A LYS 40.A N SER 59.A O no hydrogen 3.078 N/A ILE 42.A N GLY 57.A O no hydrogen 2.993 N/A SER 43.A OG SER 167.A O no hydrogen 3.378 N/A SER 44.A N TYR 55.A O no hydrogen 3.203 N/A SER 44.A OG TYR 55.A O no hydrogen 3.479 N/A THR 46.A OG1 SER 43.A O no hydrogen 3.418 N/A GLY 48.A N SER 44.A O no hydrogen 3.039 N/A GLY 48.A N GLU 45.A O no hydrogen 3.208 N/A SER 49.A OG ASN 53.A O no hydrogen 3.364 N/A THR 54.A N ASN 51.A O no hydrogen 3.166 N/A THR 54.A OG1 ASN 51.A O no hydrogen 2.538 N/A TYR 55.A N SER 44.A OG no hydrogen 3.303 N/A GLY 57.A N ILE 42.A O no hydrogen 3.048 N/A TYR 58.A N TYR 160.A O no hydrogen 3.050 N/A SER 59.A N LYS 40.A O no hydrogen 2.844 N/A THR 60.A N TYR 158.A O no hydrogen 3.193 N/A THR 60.A OG1 TYR 158.A O no hydrogen 2.850 N/A TRP 62.A N THR 60.A OG1 no hydrogen 3.325 N/A GLY 63.A N ILE 431.A O no hydrogen 2.903 N/A TYR 64.A N PRO 156.A O no hydrogen 3.362 N/A PHE 65.A N ILE 429.A O no hydrogen 3.147 N/A ASN 68.A N ASP 66.A OD2 no hydrogen 3.315 N/A ASN 68.A ND2 TRP 401.A O no hydrogen 3.008 N/A ARG 69.A NE GLN 397.A O no hydrogen 3.280 N/A ARG 69.A NH2 GLN 397.A O no hydrogen 2.949 N/A PHE 70.A N GLY 398.A O no hydrogen 3.298 N/A CYS 72.A N ARG 69.A O no hydrogen 3.209 N/A CYS 72.A SG LEU 145.A O no hydrogen 3.375 N/A HIS 73.A N PHE 70.A O no hydrogen 3.087 N/A HIS 73.A NE2 PHE 67.A O no hydrogen 2.928 N/A PHE 74.A N PHE 70.A O no hydrogen 2.909 N/A ARG 77.A NE GLN 80.A OE1 no hydrogen 3.230 N/A TRP 79.A N SER 75.A O no hydrogen 2.919 N/A GLN 80.A N PRO 76.A O no hydrogen 2.956 N/A GLN 80.A NE2 TYR 483.A O no hydrogen 2.935 N/A ARG 81.A N ARG 77.A O no hydrogen 3.013 N/A ARG 81.A NH1 ASP 78.A OD1 no hydrogen 2.637 N/A LEU 82.A N ASP 78.A O no hydrogen 2.985 N/A ILE 83.A N TRP 79.A O no hydrogen 2.966 N/A ASN 84.A N GLN 80.A O no hydrogen 2.965 N/A ASN 84.A ND2 TYR 483.A O no hydrogen 3.218 N/A ASN 85.A N ARG 81.A O no hydrogen 3.142 N/A ASN 85.A ND2 ARG 81.A O no hydrogen 2.647 N/A ASN 86.A ND2 LEU 82.A O no hydrogen 3.386 N/A TRP 87.A N GLN 470.A O no hydrogen 2.940 N/A TRP 87.A NE1 THR 515.A O no hydrogen 3.155 N/A GLY 88.A N GLN 470.A O no hydrogen 3.356 N/A ARG 90.A N GLU 468.A O no hydrogen 3.181 N/A ARG 90.A NE GLU 468.A OE2 no hydrogen 3.274 N/A ARG 90.A NH1 VAL 201.A O no hydrogen 2.716 N/A ARG 90.A NH2 GLU 468.A OE2 no hydrogen 3.059 N/A LYS 92.A N GLU 466.A O no hydrogen 2.771 N/A LYS 92.A NZ GLU 468.A OE2 no hydrogen 3.565 N/A LEU 94.A N TYR 196.A O no hydrogen 3.084 N/A ARG 95.A N GLU 464.A O no hydrogen 2.959 N/A PHE 96.A N PHE 194.A O no hydrogen 3.027 N/A LYS 97.A N SER 462.A O no hydrogen 3.015 N/A LEU 98.A N PHE 192.A O no hydrogen 3.131 N/A PHE 99.A N GLN 460.A O no hydrogen 3.108 N/A ASN 100.A N SER 7.A OG no hydrogen 3.317 N/A GLN 102.A N THR 458.A O no hydrogen 2.963 N/A LYS 104.A N TYR 456.A O no hydrogen 3.029 N/A LYS 104.A NZ ASN 117.A OD1 no hydrogen 3.150 N/A GLU 105.A N ALA 116.A O no hydrogen 2.920 N/A VAL 106.A N THR 454.A O no hydrogen 3.045 N/A THR 107.A N THR 114.A O no hydrogen 3.051 N/A THR 108.A OG1 THR 113.A OG1 no hydrogen 3.413 N/A ASN 109.A N VAL 112.A O no hydrogen 2.888 N/A VAL 112.A N ASN 109.A O no hydrogen 2.516 N/A THR 113.A OG1 THR 108.A OG1 no hydrogen 3.413 N/A THR 114.A N THR 107.A O no hydrogen 2.775 N/A THR 114.A OG1 THR 107.A OG1 no hydrogen 2.411 N/A ALA 116.A N GLU 105.A O no hydrogen 3.076 N/A ASN 118.A N VAL 103.A O no hydrogen 2.932 N/A ASN 118.A ND2 GLN 455.A OE1 no hydrogen 2.748 N/A SER 121.A OG GLN 455.A OE1 no hydrogen 3.303 N/A THR 122.A OG1 THR 434.A OG1 no hydrogen 3.339 N/A ILE 123.A N LEU 186.A O no hydrogen 3.047 N/A GLN 124.A N LYS 432.A O no hydrogen 2.913 N/A VAL 125.A N GLN 184.A O no hydrogen 3.210 N/A PHE 126.A N LEU 430.A O no hydrogen 3.199 N/A ASP 128.A N GLN 428.A O no hydrogen 3.095 N/A TYR 131.A N ASP 128.A O no hydrogen 3.308 N/A TYR 131.A OH PRO 425.A O no hydrogen 2.452 N/A GLN 132.A N ASP 128.A OD2 no hydrogen 3.460 N/A LEU 133.A N ASP 128.A OD1 no hydrogen 2.894 N/A TYR 135.A OH PRO 426.A O no hydrogen 2.748 N/A VAL 136.A N GLN 428.A OE1 no hydrogen 3.095 N/A CYS 144.A SG LEU 145.A O no hydrogen 3.215 N/A LEU 145.A N ASP 66.A O no hydrogen 3.286 N/A ASP 151.A N PHE 148.A O no hydrogen 3.252 N/A PHE 153.A N THR 28.A O no hydrogen 3.199 N/A ILE 155.A N ALA 30.A O no hydrogen 3.312 N/A GLN 157.A NE2 THR 60.A O no hydrogen 2.906 N/A TYR 158.A N TRP 62.A O no hydrogen 2.989 N/A TYR 158.A OH PRO 134.A O no hydrogen 2.934 N/A TYR 160.A N TYR 58.A O no hydrogen 3.211 N/A THR 162.A N PHE 56.A O no hydrogen 3.113 N/A LEU 163.A N THR 162.A OG1 no hydrogen 2.830 N/A ASN 164.A ND2 GLY 166.A O no hydrogen 2.764 N/A ASN 165.A N GLN 168.A O no hydrogen 3.190 N/A GLN 168.A N ASN 165.A O no hydrogen 3.373 N/A VAL 170.A N SER 173.A OG no hydrogen 3.404 N/A SER 173.A N VAL 170.A O no hydrogen 3.189 N/A SER 173.A OG LEU 163.A O no hydrogen 2.724 N/A SER 173.A OG VAL 170.A O no hydrogen 3.420 N/A SER 174.A N THR 162.A OG1 no hydrogen 3.307 N/A TYR 176.A N TYR 160.A OH no hydrogen 2.866 N/A LEU 178.A N TYR 39.A OH no hydrogen 3.023 N/A TYR 180.A N CYS 177.A O no hydrogen 3.388 N/A PHE 181.A N LEU 178.A O no hydrogen 3.344 N/A GLN 184.A N VAL 125.A O no hydrogen 2.999 N/A GLN 184.A NE2 ASN 191.A O no hydrogen 3.352 N/A LEU 186.A N ILE 123.A O no hydrogen 3.057 N/A ARG 187.A N ASN 190.A OD1 no hydrogen 3.214 N/A THR 188.A OG1 ILE 101.A O no hydrogen 2.400 N/A ASN 190.A N ARG 187.A O no hydrogen 3.210 N/A ASN 191.A ND2 SER 7.A O no hydrogen 3.272 N/A PHE 192.A N LEU 98.A O no hydrogen 3.057 N/A PHE 194.A N PHE 96.A O no hydrogen 3.216 N/A TYR 196.A N LEU 94.A O no hydrogen 3.149 N/A TYR 196.A OH HIS 424.A O no hydrogen 2.668 N/A PHE 198.A N LYS 92.A O no hydrogen 3.062 N/A HIS 204.A N PHE 89.A O no hydrogen 2.975 N/A HIS 204.A NE2 ASP 393.A OD1 no hydrogen 3.138 N/A SER 206.A N TRP 87.A O no hydrogen 2.977 N/A ALA 208.A N LEU 514.A O no hydrogen 2.861 N/A SER 210.A N ARG 516.A O no hydrogen 2.924 N/A SER 210.A OG ARG 516.A O no hydrogen 3.394 N/A SER 212.A OG ASP 214.A OD1 no hydrogen 2.529 N/A LEU 213.A N PRO 350.A O no hydrogen 3.268 N/A ASP 214.A N ASP 214.A OD1 no hydrogen 2.497 N/A ARG 215.A N SER 212.A O no hydrogen 3.178 N/A ARG 215.A NH1 ASP 214.A O no hydrogen 2.980 N/A LEU 220.A N ASN 218.A OD1 no hydrogen 3.141 N/A GLN 223.A N GLY 249.A O no hydrogen 3.370 N/A GLN 223.A NE2 ALA 258.A O no hydrogen 3.433 N/A TYR 227.A N TYR 247.A O no hydrogen 3.410 N/A ALA 229.A N GLN 245.A O no hydrogen 2.836 N/A ARG 230.A N GLN 245.A O no hydrogen 3.445 N/A GLN 232.A NE2 GLY 240.A O no hydrogen 2.942 N/A SER 233.A N ASN 241.A O no hydrogen 3.182 N/A ASN 234.A ND2 GLY 237.A O no hydrogen 2.182 N/A GLU 243.A N THR 231.A O no hydrogen 3.088 N/A GLN 245.A N ARG 230.A O no hydrogen 3.502 N/A TYR 247.A N TYR 227.A O no hydrogen 2.973 N/A GLN 248.A NE2 GLN 223.A O no hydrogen 3.091 N/A THR 253.A OG1 GLY 250.A O no hydrogen 3.278 N/A GLU 256.A N GLU 256.A OE1 no hydrogen 2.290 N/A GLN 257.A N ALA 255.A O no hydrogen 2.845 N/A GLN 257.A NE2 GLY 250.A O no hydrogen 2.567 N/A LYS 259.A NZ GLN 257.A O no hydrogen 3.397 N/A LEU 262.A N GLY 386.A O no hydrogen 3.080 N/A CYS 266.A N GLN 381.A O no hydrogen 3.258 N/A ARG 268.A N ASN 379.A O no hydrogen 3.308 N/A ARG 268.A NE THR 356.A O no hydrogen 3.164 N/A ARG 268.A NH1 ASN 379.A OD1 no hydrogen 2.960 N/A ARG 268.A NH2 THR 356.A O no hydrogen 3.266 N/A GLN 269.A N ALA 355.A O no hydrogen 3.236 N/A GLN 269.A NE2 VAL 301.A O no hydrogen 3.455 N/A GLN 269.A NE2 SER 321.A O no hydrogen 3.685 N/A ARG 271.A N GLN 270.A OE1 no hydrogen 2.721 N/A VAL 272.A N PHE 318.A O no hydrogen 2.900 N/A SER 273.A N ASN 279.A OD1 no hydrogen 2.584 N/A SER 273.A OG GLN 278.A OE1 no hydrogen 3.132 N/A LYS 274.A N ARG 316.A O no hydrogen 2.870 N/A THR 275.A N SER 273.A OG no hydrogen 2.770 N/A GLN 278.A N THR 275.A O no hydrogen 2.825 N/A ASN 279.A N THR 275.A O no hydrogen 3.033 N/A ASN 279.A ND2 SER 273.A O no hydrogen 2.762 N/A SER 282.A N ASN 280.A O no hydrogen 2.949 N/A LYS 291.A NZ TRP 286.A O no hydrogen 2.903 N/A TYR 292.A N SER 299.A O no hydrogen 3.136 N/A LEU 294.A N ARG 297.A O no hydrogen 3.045 N/A ARG 297.A N LEU 294.A O no hydrogen 3.293 N/A ARG 297.A NH1 ASN 164.A OD1 no hydrogen 3.359 N/A ASN 298.A ND2 TYR 292.A O no hydrogen 3.674 N/A SER 299.A N TYR 292.A O no hydrogen 3.269 N/A VAL 301.A N THR 290.A O no hydrogen 2.837 N/A ALA 308.A N PRO 353.A O no hydrogen 3.146 N/A HIS 310.A ND1 LYS 311.A O no hydrogen 2.728 N/A LYS 311.A NZ GLU 357.A OE1 no hydrogen 3.072 N/A ARG 316.A NE GLN 278.A OE1 no hydrogen 2.977 N/A ARG 316.A NH2 GLN 278.A OE1 no hydrogen 3.160 N/A PHE 317.A N GLU 314.A O no hydrogen 3.255 N/A PHE 318.A N VAL 272.A O no hydrogen 2.962 N/A SER 320.A N GLN 270.A O no hydrogen 2.923 N/A SER 321.A OG VAL 301.A O no hydrogen 2.477 N/A PHE 326.A N LEU 341.A O no hydrogen 2.825 N/A LYS 328.A N ASN 339.A O no hydrogen 3.278 N/A LYS 328.A NZ GLU 338.A O no hydrogen 3.227 N/A THR 332.A OG1 LYS 334.A O no hydrogen 2.509 N/A THR 332.A OG1 THR 335.A OG1 no hydrogen 3.135 N/A THR 335.A OG1 THR 332.A O no hydrogen 3.206 N/A THR 335.A OG1 THR 332.A OG1 no hydrogen 3.135 N/A THR 336.A OG1 GLU 338.A OE1 no hydrogen 2.845 N/A LEU 337.A N THR 336.A OG1 no hydrogen 2.531 N/A GLU 338.A N GLU 338.A OE1 no hydrogen 3.143 N/A LEU 341.A N PHE 326.A O no hydrogen 2.554 N/A THR 343.A N LEU 324.A O no hydrogen 3.297 N/A THR 343.A OG1 LEU 324.A O no hydrogen 3.266 N/A GLU 345.A N THR 309.A OG1 no hydrogen 2.909 N/A ARG 349.A NE GLU 346.A O no hydrogen 3.198 N/A THR 351.A N ILE 348.A O no hydrogen 3.205 N/A THR 351.A OG1 ASN 352.A OD1 no hydrogen 2.725 N/A ASN 352.A N ILE 348.A O no hydrogen 2.843 N/A ASN 352.A ND2 ALA 306.A O no hydrogen 3.317 N/A ASN 352.A ND2 GLN 390.A O no hydrogen 3.147 N/A ALA 355.A N ALA 308.A O no hydrogen 2.923 N/A TYR 359.A N VAL 378.A O no hydrogen 2.930 N/A TYR 359.A OH PRO 263.A O no hydrogen 3.174 N/A VAL 362.A N GLN 376.A O no hydrogen 3.171 N/A SER 364.A N GLN 374.A O no hydrogen 3.271 N/A ASN 365.A ND2 ALA 372.A O no hydrogen 3.354 N/A ALA 368.A N THR 371.A O no hydrogen 3.442 N/A GLN 374.A N ASN 365.A OD1 no hydrogen 3.111 N/A GLN 376.A N VAL 362.A O no hydrogen 2.970 N/A VAL 378.A N GLY 360.A O no hydrogen 3.170 N/A GLN 381.A N CYS 266.A O no hydrogen 3.258 N/A GLN 381.A NE2 GLY 382.A O no hydrogen 3.580 N/A MET 387.A N LEU 384.A O no hydrogen 3.172 N/A VAL 388.A N LEU 262.A O no hydrogen 3.085 N/A GLN 390.A N ASN 352.A OD1 no hydrogen 3.059 N/A ASN 391.A ND2 HIS 412.A NE2 no hydrogen 3.517 N/A ASP 393.A N GLU 345.A OE2 no hydrogen 3.345 N/A VAL 394.A N ASP 393.A OD1 no hydrogen 2.765 N/A TYR 395.A OH GLU 345.A OE2 no hydrogen 2.826 N/A LEU 396.A N ILE 509.A O no hydrogen 3.194 N/A GLY 398.A N TYR 395.A O no hydrogen 3.054 N/A ILE 400.A N ASN 68.A OD1 no hydrogen 2.958 N/A TRP 401.A N ASN 68.A OD1 no hydrogen 3.071 N/A TRP 401.A NE1 TYR 135.A OH no hydrogen 3.271 N/A ALA 402.A N PHE 420.A O no hydrogen 3.114 N/A ILE 404.A N LEU 422.A O no hydrogen 2.903 N/A THR 407.A OG1 PRO 405.A O no hydrogen 3.372 N/A THR 407.A OG1 GLY 409.A O no hydrogen 3.445 N/A SER 414.A N HIS 412.A O no hydrogen 2.613 N/A GLY 418.A N PRO 415.A O no hydrogen 3.003 N/A PHE 420.A N ILE 400.A O no hydrogen 2.877 N/A LEU 422.A N ALA 402.A O no hydrogen 3.019 N/A LYS 423.A N GLU 199.A OE2 no hydrogen 3.416 N/A HIS 424.A N GLU 199.A OE1 no hydrogen 3.131 N/A GLN 428.A NE2 PRO 134.A O no hydrogen 3.078 N/A LEU 430.A N PHE 126.A O no hydrogen 3.098 N/A ILE 431.A N GLY 63.A O no hydrogen 3.117 N/A LYS 432.A N GLN 124.A O no hydrogen 3.018 N/A LYS 432.A NZ GLU 179.A OE2 no hydrogen 2.471 N/A ASN 433.A ND2 LEU 31.A O no hydrogen 3.316 N/A ASN 433.A ND2 PRO 32.A O no hydrogen 3.374 N/A THR 434.A OG1 THR 122.A OG1 no hydrogen 3.339 N/A THR 434.A OG1 GLN 124.A OE1 no hydrogen 3.275 N/A ALA 438.A N SER 451.A O no hydrogen 2.949 N/A ILE 453.A N VAL 436.A O no hydrogen 3.143 N/A TYR 456.A N LYS 104.A O no hydrogen 3.224 N/A SER 457.A N LEU 31.A O no hydrogen 3.075 N/A SER 457.A OG ASN 433.A OD1 no hydrogen 3.054 N/A THR 458.A N GLN 102.A O no hydrogen 2.979 N/A THR 458.A OG1 TRP 29.A O no hydrogen 2.688 N/A GLY 459.A N TRP 29.A O no hydrogen 3.372 N/A GLN 460.A N PHE 99.A O no hydrogen 3.046 N/A VAL 461.A N ARG 27.A O no hydrogen 3.130 N/A SER 462.A N LYS 97.A O no hydrogen 3.065 N/A VAL 463.A N SER 25.A O no hydrogen 3.120 N/A GLU 464.A N ARG 95.A O no hydrogen 2.950 N/A ILE 465.A N THR 23.A O no hydrogen 3.139 N/A GLU 466.A N LYS 93.A O no hydrogen 3.161 N/A TRP 467.A N VAL 21.A O no hydrogen 2.839 N/A GLU 468.A N ARG 90.A O no hydrogen 2.878 N/A LEU 469.A N ASP 19.A O no hydrogen 2.780 N/A GLN 470.A N GLY 88.A O no hydrogen 2.787 N/A LYS 471.A NZ ASN 86.A OD1 no hydrogen 2.492 N/A ARG 476.A N SER 474.A OG no hydrogen 3.392 N/A ARG 476.A NE ASN 478.A O no hydrogen 3.303 N/A ARG 476.A NH2 PRO 479.A O no hydrogen 2.873 N/A GLN 482.A NE2 ASN 84.A O no hydrogen 3.475 N/A GLN 482.A NE2 ILE 481.A O no hydrogen 3.391 N/A TYR 483.A N ASN 84.A OD1 no hydrogen 3.160 N/A THR 484.A OG1 SER 485.A O no hydrogen 3.381 N/A SER 485.A OG ASN 486.A O no hydrogen 3.545 N/A GLN 490.A NE2 GLY 492.A O no hydrogen 2.621 N/A GLN 490.A NE2 ASP 494.A OD2 no hydrogen 3.318 N/A ASP 498.A N VAL 502.A O no hydrogen 3.311 N/A GLN 500.A N ASP 498.A OD1 no hydrogen 2.614 N/A GLY 501.A N ASP 498.A O no hydrogen 3.174 N/A ARG 507.A NH1 ASP 494.A OD1 no hydrogen 3.365 N/A ARG 507.A NH2 ASP 494.A OD1 no hydrogen 3.471 N/A THR 511.A N ASP 393.A OD2 no hydrogen 3.025 N/A THR 511.A OG1 ASP 393.A OD1 no hydrogen 2.593 N/A ARG 512.A NE SER 205.A O no hydrogen 3.098 N/A ARG 512.A NH1 ASN 391.A O no hydrogen 3.065 N/A ARG 512.A NH2 SER 205.A O no hydrogen 3.548 N/A ARG 512.A NH2 SER 205.A OG no hydrogen 3.290 N/A ARG 512.A NH2 ASN 391.A O no hydrogen 3.171 N/A THR 515.A OG1 GLU 480.A OE2 no hydrogen 2.488 N/A