Finding intermodel H-bonds Finding intramodel H-bonds Constraints relaxed by 0.4 angstroms and 20 degrees Models used: #0 1olx_B.cif H-bonds (donor, acceptor, hydrogen, D..A dist, D-H..A dist): THR 11.A OG1 GLU 193.A OE1 no hydrogen 2.644 N/A GLN 12.A N VAL 194.A O no hydrogen 3.060 N/A MET 14.A N GLU 192.A O no hydrogen 2.826 N/A ASN 15.A N GLN 18.A OE1 no hydrogen 2.733 N/A LEU 16.A N ALA 190.A O no hydrogen 3.110 N/A PHE 17.A N TYR 187.A O no hydrogen 3.073 N/A GLN 18.A N ASN 15.A OD1 no hydrogen 2.871 N/A SER 19.A N ASN 15.A O no hydrogen 2.979 N/A SER 19.A OG LEU 16.A O no hydrogen 2.869 N/A SER 19.A OG PRO 161.A O no hydrogen 3.153 N/A VAL 20.A N LEU 16.A O no hydrogen 3.105 N/A VAL 20.A N PHE 17.A O no hydrogen 3.185 N/A THR 21.A N PHE 17.A O no hydrogen 3.168 N/A THR 21.A OG1 PHE 17.A O no hydrogen 3.171 N/A THR 21.A OG1 CYS 49.A O no hydrogen 2.725 N/A SER 22.A N GLN 18.A O no hydrogen 2.962 N/A ALA 23.A N SER 19.A O no hydrogen 3.076 N/A LEU 24.A N VAL 20.A O no hydrogen 2.894 N/A ASP 25.A N THR 21.A O no hydrogen 2.839 N/A ASN 26.A N SER 22.A O no hydrogen 2.862 N/A ASN 26.A ND2 ILE 196.A O no hydrogen 3.431 N/A SER 27.A N ALA 23.A O no hydrogen 2.977 N/A SER 27.A OG ALA 23.A O no hydrogen 2.858 N/A LEU 28.A N LEU 24.A O no hydrogen 3.017 N/A ALA 29.A N ASP 25.A O no hydrogen 2.969 N/A LYS 30.A N ASN 26.A O no hydrogen 2.994 N/A LYS 30.A NZ GLU 173.A OE2 no hydrogen 2.649 N/A THR 33.A N ASP 31.A OD1 no hydrogen 3.067 N/A THR 33.A OG1 ASP 31.A OD1 no hydrogen 2.765 N/A ALA 34.A N ASP 31.A O no hydrogen 2.980 N/A VAL 35.A N THR 85.A O no hydrogen 3.014 N/A ILE 36.A N ARG 61.A O no hydrogen 2.623 N/A PHE 37.A N ILE 87.A O no hydrogen 3.167 N/A GLY 38.A N PHE 63.A O no hydrogen 3.414 N/A ALA 42.A N ASN 64.A OD1 no hydrogen 2.931 N/A GLY 44.A N VAL 41.A O no hydrogen 2.956 N/A ARG 48.A N GLY 45.A O no hydrogen 2.901 N/A CYS 49.A SG PHE 47.A O no hydrogen 3.973 N/A THR 50.A N GLY 44.A O no hydrogen 2.999 N/A THR 50.A OG1 VAL 41.A O no hydrogen 2.738 N/A VAL 51.A N ARG 48.A O no hydrogen 3.529 N/A LEU 53.A N THR 50.A O no hydrogen 3.203 N/A ARG 54.A NH1 VAL 62.A O no hydrogen 2.799 N/A LYS 56.A N GLY 52.A O no hydrogen 3.030 N/A LYS 56.A NZ ASP 25.A OD1 no hydrogen 3.234 N/A LYS 56.A NZ ASP 25.A OD2 no hydrogen 3.080 N/A TYR 57.A N LEU 53.A O no hydrogen 2.816 N/A TYR 57.A OH ASP 25.A OD1 no hydrogen 2.536 N/A GLY 58.A N ARG 54.A O no hydrogen 2.786 N/A ARG 61.A N GLY 58.A O no hydrogen 3.193 N/A ARG 61.A NE ALA 34.A O no hydrogen 3.104 N/A ARG 61.A NH1 LEU 28.A O no hydrogen 3.489 N/A ARG 61.A NH2 LEU 28.A O no hydrogen 3.192 N/A ARG 61.A NH2 ALA 34.A O no hydrogen 2.988 N/A VAL 62.A N GLY 58.A O no hydrogen 3.251 N/A PHE 63.A N ILE 36.A O no hydrogen 3.053 N/A THR 65.A N GLY 38.A O no hydrogen 3.092 N/A THR 65.A OG1 PRO 66.A O no hydrogen 3.076 N/A GLU 69.A N GLU 69.A OE1 no hydrogen 2.699 N/A ILE 72.A N CYS 68.A O no hydrogen 2.936 N/A VAL 73.A N GLU 69.A O no hydrogen 3.160 N/A GLY 74.A N GLN 70.A O no hydrogen 3.033 N/A PHE 75.A N GLY 71.A O no hydrogen 2.676 N/A GLY 76.A N ILE 72.A O no hydrogen 2.897 N/A ILE 77.A N VAL 73.A O no hydrogen 2.792 N/A GLY 78.A N GLY 74.A O no hydrogen 3.024 N/A ILE 79.A N PHE 75.A O no hydrogen 3.072 N/A ALA 80.A N GLY 76.A O no hydrogen 2.982 N/A VAL 81.A N ILE 77.A O no hydrogen 2.827 N/A THR 82.A N ILE 79.A O no hydrogen 3.095 N/A THR 82.A OG1 ILE 79.A O no hydrogen 2.733 N/A GLY 83.A N ALA 80.A O no hydrogen 2.722 N/A THR 85.A N THR 33.A OG1 no hydrogen 3.048 N/A THR 85.A OG1 ASP 31.A OD2 no hydrogen 2.692 N/A ALA 86.A N SER 122.A O no hydrogen 2.873 N/A ILE 87.A N VAL 35.A O no hydrogen 3.001 N/A ALA 88.A N THR 124.A O no hydrogen 2.801 N/A GLU 89.A N PHE 37.A O no hydrogen 2.941 N/A ILE 90.A N ARG 126.A O no hydrogen 3.146 N/A GLN 91.A NE2 GLU 39.A O no hydrogen 3.255 N/A GLN 91.A NE2 ASP 40.A OD2 no hydrogen 2.851 N/A ALA 93.A N PRO 128.A O no hydrogen 2.858 N/A TYR 95.A N PHE 92.A O no hydrogen 2.860 N/A ILE 96.A N ALA 93.A O no hydrogen 3.092 N/A ALA 99.A N ILE 96.A O no hydrogen 2.865 N/A PHE 100.A N PHE 97.A O no hydrogen 2.844 N/A ILE 103.A N ALA 99.A O no hydrogen 2.927 N/A VAL 104.A N PHE 100.A O no hydrogen 2.808 N/A ASN 105.A N ASP 101.A O no hydrogen 3.019 N/A ASN 105.A ND2 ASP 101.A OD1 no hydrogen 2.936 N/A ALA 107.A N GLN 102.A O no hydrogen 2.805 N/A ALA 108.A N ILE 103.A O no hydrogen 3.036 N/A LYS 109.A N GLU 106.A O no hydrogen 3.136 N/A LYS 109.A NZ VAL 104.A O no hydrogen 2.795 N/A TYR 110.A N ALA 107.A O no hydrogen 3.366 N/A ARG 111.A NH1 ASP 116.A OD1 no hydrogen 2.693 N/A ARG 111.A NH2 LYS 175.A O no hydrogen 2.647 N/A ARG 113.A N LYS 109.A O no hydrogen 3.032 N/A ARG 113.A NH1 GLU 106.A OE2 no hydrogen 3.084 N/A ARG 113.A NH2 GLU 106.A OE1 no hydrogen 2.846 N/A SER 114.A OG TYR 110.A O no hydrogen 3.217 N/A SER 114.A OG ARG 111.A O no hydrogen 3.262 N/A SER 114.A OG PHE 118.A O no hydrogen 3.009 N/A GLY 115.A N TYR 112.A O no hydrogen 3.124 N/A ASP 116.A N ARG 111.A O no hydrogen 3.023 N/A LEU 117.A N SER 114.A O no hydrogen 3.230 N/A PHE 118.A N SER 114.A OG no hydrogen 3.117 N/A CYS 120.A SG ALA 107.A O no hydrogen 3.465 N/A GLY 121.A N ASN 119.A OD1 no hydrogen 2.870 N/A SER 122.A OG ALA 84.A O no hydrogen 2.683 N/A LEU 123.A N CYS 120.A O no hydrogen 3.289 N/A THR 124.A N ALA 86.A O no hydrogen 2.827 N/A ILE 125.A N CYS 178.A O no hydrogen 2.780 N/A ARG 126.A N ALA 88.A O no hydrogen 2.915 N/A ARG 126.A NE GLU 182.A OE2 no hydrogen 2.738 N/A ARG 126.A NH1 GLU 89.A OE1 no hydrogen 2.638 N/A ARG 126.A NH2 GLU 89.A OE1 no hydrogen 3.472 N/A ARG 126.A NH2 GLU 182.A OE1 no hydrogen 2.857 N/A ARG 126.A NH2 GLU 182.A OE2 no hydrogen 3.349 N/A SER 127.A N PHE 180.A O no hydrogen 2.972 N/A SER 127.A OG ILE 90.A O no hydrogen 3.062 N/A SER 127.A OG PRO 128.A O no hydrogen 3.448 N/A TRP 129.A N GLU 182.A O no hydrogen 2.621 N/A TRP 129.A NE1 GLU 144.A OE1 no hydrogen 2.860 N/A GLY 130.A N GLN 141.A O no hydrogen 3.024 N/A CYS 131.A N GLU 273.A OE1 no hydrogen 2.873 N/A CYS 131.A SG GLU 273.A OE1 no hydrogen 3.319 N/A CYS 131.A SG GLU 315.A OE2 no hydrogen 3.530 N/A GLY 133.A N GLU 315.A OE2 no hydrogen 2.800 N/A SER 140.A N ASP 94.A OD2 no hydrogen 3.060 N/A SER 140.A OG ALA 136.A O no hydrogen 2.598 N/A GLN 141.A N ASP 94.A OD2 no hydrogen 2.900 N/A GLN 141.A NE2 LEU 137.A O no hydrogen 2.965 N/A GLU 144.A N GLU 144.A OE1 no hydrogen 2.727 N/A PHE 146.A N PRO 143.A O no hydrogen 3.057 N/A PHE 147.A N GLU 144.A O no hydrogen 3.172 N/A ALA 148.A N GLU 144.A O no hydrogen 3.024 N/A ALA 148.A N ALA 145.A O no hydrogen 3.196 N/A CYS 150.A N PHE 147.A O no hydrogen 2.970 N/A CYS 150.A SG VAL 104.A O no hydrogen 3.841 N/A CYS 150.A SG PRO 151.A O no hydrogen 3.981 N/A ILE 153.A N CYS 150.A O no hydrogen 3.495 N/A LYS 154.A N PRO 177.A O no hydrogen 3.203 N/A LYS 154.A NZ ASP 174.A OD1 no hydrogen 3.147 N/A LYS 154.A NZ ASP 174.A OD2 no hydrogen 3.322 N/A VAL 155.A N ILE 251.A O no hydrogen 3.209 N/A VAL 156.A N ILE 179.A O no hydrogen 2.960 N/A ILE 157.A N ARG 248.A O no hydrogen 2.773 N/A ARG 159.A NH1 GLU 207.A OE1 no hydrogen 2.757 N/A ARG 159.A NH1 ASP 246.A OD2 no hydrogen 2.787 N/A ARG 159.A NH2 GLU 207.A OE1 no hydrogen 2.958 N/A SER 160.A OG GLU 192.A OE2 no hydrogen 3.030 N/A PHE 162.A N GLU 192.A OE2 no hydrogen 2.999 N/A ALA 164.A N SER 160.A O no hydrogen 2.710 N/A LYS 165.A N PRO 161.A O no hydrogen 3.233 N/A LYS 165.A NZ SER 22.A OG no hydrogen 2.800 N/A LYS 165.A NZ ASN 26.A OD1 no hydrogen 2.830 N/A LYS 165.A NZ PRO 195.A O no hydrogen 2.823 N/A LYS 165.A NZ GLU 197.A O no hydrogen 3.407 N/A GLY 166.A N PHE 162.A O no hydrogen 3.344 N/A LEU 167.A N GLN 163.A O no hydrogen 2.877 N/A LEU 168.A N ALA 164.A O no hydrogen 2.823 N/A LEU 169.A N LYS 165.A O no hydrogen 3.092 N/A SER 170.A N GLY 166.A O no hydrogen 3.290 N/A SER 170.A OG GLY 166.A O no hydrogen 3.366 N/A SER 170.A OG ILE 201.A O no hydrogen 2.518 N/A CYS 171.A N LEU 167.A O no hydrogen 2.991 N/A CYS 171.A SG LEU 167.A O no hydrogen 3.412 N/A ILE 172.A N LEU 168.A O no hydrogen 2.799 N/A GLU 173.A N LEU 169.A O no hydrogen 3.078 N/A ASP 174.A N SER 170.A O no hydrogen 2.625 N/A ASP 174.A N CYS 171.A O no hydrogen 3.161 N/A ASN 176.A ND2 ASP 174.A OD2 no hydrogen 2.766 N/A CYS 178.A N LEU 123.A O no hydrogen 3.023 N/A CYS 178.A SG CYS 171.A O no hydrogen 3.860 N/A CYS 178.A SG ASN 176.A O no hydrogen 3.326 N/A ILE 179.A N LYS 154.A O no hydrogen 2.770 N/A PHE 180.A N ILE 125.A O no hydrogen 2.713 N/A PHE 181.A N VAL 156.A O no hydrogen 2.983 N/A GLU 182.A N SER 127.A O no hydrogen 2.922 N/A LYS 184.A N TRP 129.A O no hydrogen 2.963 N/A LYS 184.A NZ GLY 130.A O no hydrogen 2.573 N/A LYS 184.A NZ ALA 139.A O no hydrogen 2.986 N/A LEU 186.A N PRO 183.A O no hydrogen 3.011 N/A TYR 187.A N LYS 184.A O no hydrogen 3.260 N/A TYR 187.A OH GLU 182.A OE1 no hydrogen 2.461 N/A ALA 189.A N LEU 186.A O no hydrogen 3.093 N/A GLU 192.A N MET 14.A O no hydrogen 3.014 N/A VAL 194.A N GLN 12.A O no hydrogen 2.843 N/A ILE 196.A N GLN 10.A O no hydrogen 3.054 N/A TYR 199.A OH PHE 162.A O no hydrogen 2.655 N/A ASN 200.A ND2 SER 170.A OG no hydrogen 3.291 N/A ASN 200.A ND2 GLU 173.A OE1 no hydrogen 2.767 N/A ILE 201.A N GLY 166.A O no hydrogen 3.184 N/A SER 204.A N THR 249.A OG1 no hydrogen 2.824 N/A SER 204.A OG PRO 252.A O no hydrogen 2.890 N/A GLN 205.A NE2 SER 204.A O no hydrogen 2.941 N/A ALA 206.A N ASP 254.A OD2 no hydrogen 2.816 N/A GLU 207.A N ASP 246.A O no hydrogen 2.865 N/A ILE 209.A N VAL 244.A O no hydrogen 2.790 N/A GLN 210.A NE2 CYS 242.A O no hydrogen 3.133 N/A GLY 212.A N GLU 243.A OE1 no hydrogen 3.173 N/A SER 213.A N SER 241.A OG no hydrogen 3.040 N/A SER 213.A OG ASP 214.A OD1 no hydrogen 3.512 N/A ASP 214.A N SER 241.A O no hydrogen 2.868 N/A VAL 215.A N SER 241.A O no hydrogen 3.406 N/A THR 216.A N ARG 267.A O no hydrogen 2.750 N/A THR 216.A OG1 SER 261.A OG no hydrogen 2.513 N/A THR 216.A OG1 THR 265.A OG1 no hydrogen 2.846 N/A LEU 217.A N GLU 243.A O no hydrogen 2.829 N/A VAL 218.A N LEU 269.A O no hydrogen 2.945 N/A ALA 219.A N ILE 245.A O no hydrogen 3.234 N/A TRP 220.A NE1 GLU 144.A OE2 no hydrogen 2.881 N/A GLN 223.A NE2 SER 271.A OG no hydrogen 2.883 N/A GLN 223.A NE2 PRO 320.A O no hydrogen 2.920 N/A VAL 224.A N GLY 221.A O no hydrogen 2.943 N/A HIS 225.A N THR 222.A O no hydrogen 2.870 N/A HIS 225.A NE2 ARG 159.A O no hydrogen 2.725 N/A ILE 227.A N GLN 223.A O no hydrogen 3.222 N/A ARG 228.A N VAL 224.A O no hydrogen 3.121 N/A GLU 229.A N HIS 225.A O no hydrogen 3.284 N/A VAL 230.A N VAL 226.A O no hydrogen 2.941 N/A ALA 231.A N ILE 227.A O no hydrogen 2.811 N/A SER 232.A N ARG 228.A O no hydrogen 3.128 N/A MET 233.A N GLU 229.A O no hydrogen 2.828 N/A ALA 234.A N VAL 230.A O no hydrogen 2.784 N/A LYS 235.A N ALA 231.A O no hydrogen 3.020 N/A GLU 236.A N SER 232.A O no hydrogen 2.972 N/A LYS 237.A N MET 233.A O no hydrogen 2.835 N/A LEU 238.A N ALA 234.A O no hydrogen 2.694 N/A GLY 239.A N LYS 235.A O no hydrogen 3.065 N/A VAL 240.A N ALA 234.A O no hydrogen 3.313 N/A SER 241.A N ASP 214.A OD2 no hydrogen 2.619 N/A GLU 243.A N VAL 215.A O no hydrogen 2.861 N/A VAL 244.A N GLN 210.A O no hydrogen 2.914 N/A ILE 245.A N LEU 217.A O no hydrogen 2.816 N/A ASP 246.A N GLU 207.A O no hydrogen 2.887 N/A LEU 247.A N ALA 219.A O no hydrogen 2.928 N/A ARG 248.A N ASP 246.A OD1 no hydrogen 3.131 N/A ARG 248.A NE GLN 205.A O no hydrogen 2.892 N/A ARG 248.A NH1 GLN 163.A OE1 no hydrogen 2.959 N/A ARG 248.A NH2 GLN 205.A O no hydrogen 2.978 N/A THR 249.A N LEU 247.A O no hydrogen 2.762 N/A ILE 250.A N VAL 155.A O no hydrogen 2.819 N/A VAL 255.A N TRP 253.A O no hydrogen 2.908 N/A THR 257.A N ASP 254.A OD1 no hydrogen 3.132 N/A THR 257.A OG1 ASP 254.A OD1 no hydrogen 3.244 N/A THR 257.A OG1 ASP 254.A OD2 no hydrogen 2.548 N/A CYS 259.A N VAL 255.A O no hydrogen 3.021 N/A CYS 259.A SG VAL 255.A O no hydrogen 3.471 N/A LYS 260.A N ASP 256.A O no hydrogen 2.838 N/A SER 261.A N THR 257.A O no hydrogen 3.095 N/A SER 261.A OG THR 216.A OG1 no hydrogen 2.513 N/A SER 261.A OG GLU 243.A OE2 no hydrogen 2.640 N/A VAL 262.A N ILE 258.A O no hydrogen 2.942 N/A ILE 263.A N CYS 259.A O no hydrogen 2.778 N/A LYS 264.A N LYS 260.A O no hydrogen 3.384 N/A LYS 264.A NZ GLY 212.A O no hydrogen 3.116 N/A LYS 264.A NZ GLU 243.A OE1 no hydrogen 2.789 N/A LYS 264.A NZ GLU 243.A OE2 no hydrogen 3.495 N/A THR 265.A N SER 261.A O no hydrogen 2.974 N/A THR 265.A OG1 THR 216.A OG1 no hydrogen 2.846 N/A THR 265.A OG1 SER 261.A O no hydrogen 3.301 N/A THR 265.A OG1 ARG 267.A O no hydrogen 3.093 N/A GLY 266.A N VAL 262.A O no hydrogen 2.702 N/A ARG 267.A N THR 265.A OG1 no hydrogen 3.348 N/A LEU 269.A N THR 216.A O no hydrogen 2.850 N/A ILE 270.A N SER 301.A O no hydrogen 2.802 N/A SER 271.A N VAL 218.A O no hydrogen 2.848 N/A SER 271.A OG VAL 303.A O no hydrogen 2.807 N/A HIS 272.A N VAL 303.A O no hydrogen 3.298 N/A LEU 276.A N GLY 305.A O no hydrogen 3.056 N/A THR 277.A N ASP 307.A OD1 no hydrogen 2.837 N/A THR 277.A OG1 ASP 307.A OD1 no hydrogen 3.466 N/A THR 277.A OG1 ASP 307.A OD2 no hydrogen 2.617 N/A GLY 279.A N LEU 276.A O no hydrogen 3.067 N/A SER 282.A N GLY 279.A O no hydrogen 3.198 N/A ILE 284.A N PHE 280.A O no hydrogen 3.248 N/A SER 285.A N ALA 281.A O no hydrogen 2.839 N/A SER 286.A N SER 282.A O no hydrogen 2.924 N/A SER 286.A OG SER 282.A O no hydrogen 2.954 N/A SER 286.A OG GLU 283.A O no hydrogen 3.306 N/A THR 287.A N GLU 283.A O no hydrogen 3.049 N/A THR 287.A OG1 GLU 283.A O no hydrogen 2.750 N/A VAL 288.A N ILE 284.A O no hydrogen 3.002 N/A GLN 289.A N SER 285.A O no hydrogen 2.994 N/A GLU 290.A N SER 286.A O no hydrogen 3.133 N/A GLU 290.A N THR 287.A O no hydrogen 2.945 N/A GLU 291.A N THR 287.A O no hydrogen 2.955 N/A CYS 292.A N VAL 288.A O no hydrogen 2.618 N/A CYS 292.A SG CYS 259.A O no hydrogen 3.935 N/A ASN 295.A N CYS 292.A O no hydrogen 2.890 N/A LEU 296.A N CYS 292.A O no hydrogen 3.065 N/A GLU 297.A N GLY 266.A O no hydrogen 2.832 N/A SER 301.A N LEU 268.A O no hydrogen 3.012 N/A VAL 303.A N ILE 270.A O no hydrogen 2.986 N/A GLY 305.A N ALA 274.A O no hydrogen 3.006 N/A THR 308.A N TYR 306.A O no hydrogen 2.810 N/A THR 308.A OG1 PRO 309.A O no hydrogen 2.992 N/A GLU 315.A N HIS 312.A O no hydrogen 3.382 N/A PHE 317.A N PHE 314.A O no hydrogen 2.940 N/A TYR 318.A N PHE 314.A O no hydrogen 3.234 N/A TYR 318.A N GLU 315.A O no hydrogen 2.779 N/A TYR 318.A OH TYR 306.A O no hydrogen 2.780 N/A ILE 319.A N GLU 315.A O no hydrogen 3.287 N/A LYS 322.A NZ GLU 229.A OE2 no hydrogen 2.610 N/A LYS 324.A N ASP 321.A OD1 no hydrogen 2.755 N/A LYS 324.A NZ TYR 306.A OH no hydrogen 2.841 N/A LYS 324.A NZ PHE 317.A O no hydrogen 2.658 N/A LYS 324.A NZ ILE 319.A O no hydrogen 3.356 N/A CYS 325.A N ASP 321.A O no hydrogen 2.971 N/A CYS 325.A SG SER 271.A OG no hydrogen 3.304 N/A CYS 325.A SG PRO 320.A O no hydrogen 3.510 N/A CYS 325.A SG ASP 321.A O no hydrogen 3.493 N/A TYR 326.A N LYS 322.A O no hydrogen 2.826 N/A ASP 327.A N TRP 323.A O no hydrogen 3.008 N/A ALA 328.A N LYS 324.A O no hydrogen 3.255 N/A LEU 329.A N CYS 325.A O no hydrogen 2.915 N/A ARG 330.A N TYR 326.A O no hydrogen 2.738 N/A ARG 330.A NE ASP 327.A OD1 no hydrogen 3.412 N/A ARG 330.A NH2 ASP 327.A OD1 no hydrogen 3.090 N/A LYS 331.A N ASP 327.A O no hydrogen 2.934 N/A MET 332.A N ALA 328.A O no hydrogen 2.876 N/A ILE 333.A N LEU 329.A O no hydrogen 2.757 N/A ASN 334.A N ARG 330.A O no hydrogen 3.056 N/A ASN 334.A N LYS 331.A O no hydrogen 3.235 N/A TYR 335.A N MET 332.A O no hydrogen 3.050 N/A