Finding intermodel H-bonds Finding intramodel H-bonds Constraints relaxed by 0.4 angstroms and 20 degrees Models used: #0 6lxa_A.cif H-bonds (donor, acceptor, hydrogen, D..A dist, D-H..A dist): SER 7.A N ASP 4.A OD2 no hydrogen 2.998 N/A LEU 8.A N.A ASP 4.A O no hydrogen 3.065 N/A LEU 8.A N.B ASP 4.A O no hydrogen 3.070 N/A ALA 9.A N LEU 5.A O no hydrogen 2.949 N/A LYS 10.A N LYS 6.A O no hydrogen 3.048 N/A ARG 11.A N SER 7.A O no hydrogen 2.859 N/A ARG 11.A NH1 ALA 94.A O no hydrogen 2.935 N/A ILE 12.A N.A LEU 8.A O.A no hydrogen 2.930 N/A ILE 12.A N.A LEU 8.A O.B no hydrogen 2.979 N/A ILE 12.A N.B LEU 8.A O.A no hydrogen 2.967 N/A ILE 12.A N.B LEU 8.A O.B no hydrogen 3.017 N/A TYR 13.A N ALA 9.A O no hydrogen 2.983 N/A GLU 14.A N LYS 10.A O no hydrogen 2.888 N/A ALA 15.A N ARG 11.A O no hydrogen 2.970 N/A TYR 16.A N.A ILE 12.A O.A no hydrogen 2.948 N/A TYR 16.A N.A ILE 12.A O.B no hydrogen 2.980 N/A TYR 16.A N.B ILE 12.A O.A no hydrogen 2.915 N/A TYR 16.A N.B ILE 12.A O.B no hydrogen 2.946 N/A TYR 16.A OH.A ASP 173.A OD1.A no hydrogen 2.665 N/A TYR 16.A OH.A ASP 173.A OD1.B no hydrogen 1.883 N/A LEU 17.A N TYR 13.A O no hydrogen 2.933 N/A LYS 18.A N GLU 14.A O no hydrogen 2.993 N/A ASN 19.A N ALA 15.A O no hydrogen 3.003 N/A ASN 19.A N TYR 16.A O.B no hydrogen 3.211 N/A ASN 19.A ND2 ALA 15.A O no hydrogen 2.871 N/A PHE 20.A N TYR 16.A O.A no hydrogen 3.200 N/A PHE 20.A N TYR 16.A O.B no hydrogen 3.102 N/A ASN 21.A N GLU 87.A OE2 no hydrogen 2.932 N/A ASN 21.A ND2 GLU 87.A OE2 no hydrogen 2.889 N/A LYS 24.A N ASP 173.A OD1.A no hydrogen 2.835 N/A LYS 24.A N ASP 173.A OD2.B no hydrogen 2.842 N/A LYS 24.A NZ LEU 171.A O no hydrogen 2.797 N/A VAL 25.A N ASP 173.A OD2.A no hydrogen 3.256 N/A LYS 26.A N ASN 23.A OD1 no hydrogen 2.848 N/A LYS 26.A NZ ASN 21.A O no hydrogen 2.806 N/A ALA 27.A N ASN 23.A O no hydrogen 2.921 N/A ARG 28.A N LYS 24.A O no hydrogen 2.898 N/A ARG 28.A NH2 GLU 170.A OE1 no hydrogen 2.996 N/A VAL 29.A N VAL 25.A O no hydrogen 3.004 N/A ILE 30.A N LYS 26.A O no hydrogen 3.277 N/A LEU 31.A N ALA 27.A O no hydrogen 2.812 N/A SER 32.A N ARG 28.A O no hydrogen 2.936 N/A SER 32.A OG VAL 29.A O no hydrogen 2.886 N/A GLY 33.A N ILE 30.A O no hydrogen 3.116 N/A LYS 34.A N VAL 29.A O no hydrogen 3.388 N/A PHE 40.A N.A ASN 137.A O no hydrogen 2.886 N/A PHE 40.A N.B ASN 137.A O no hydrogen 2.874 N/A ILE 42.A N PHE 139.A O no hydrogen 2.800 N/A HIS 43.A N THR 47.A OG1 no hydrogen 2.940 N/A ASP 44.A N THR 47.A OG1 no hydrogen 3.183 N/A THR 47.A N ASP 44.A OD1 no hydrogen 2.861 N/A THR 47.A OG1 ASP 44.A O no hydrogen 3.235 N/A THR 47.A OG1 ASP 44.A OD1 no hydrogen 2.709 N/A LEU 48.A N ASP 44.A O no hydrogen 2.911 N/A CYS 49.A N MET 45.A O.A no hydrogen 2.960 N/A CYS 49.A N MET 45.A O.B no hydrogen 3.009 N/A CYS 49.A SG MET 45.A O.A no hydrogen 3.384 N/A CYS 49.A SG MET 45.A O.B no hydrogen 3.370 N/A MET 50.A N GLU 46.A O no hydrogen 2.998 N/A ALA 51.A N THR 47.A O no hydrogen 2.930 N/A GLU 52.A N LEU 48.A O no hydrogen 2.874 N/A LYS 53.A N CYS 49.A O no hydrogen 3.118 N/A THR 54.A N MET 50.A O no hydrogen 3.298 N/A THR 54.A N ALA 51.A O no hydrogen 3.167 N/A LEU 55.A N ALA 51.A O no hydrogen 2.763 N/A VAL 56.A N GLU 52.A O no hydrogen 2.938 N/A LEU 59.A N VAL 56.A O no hydrogen 2.943 N/A VAL 60.A N ALA 57.A O no hydrogen 3.078 N/A ALA 61.A N LYS 58.A O no hydrogen 3.293 N/A ASN 62.A N ASN 66.A OD1 no hydrogen 2.879 N/A GLN 65.A N ASN 62.A O no hydrogen 3.119 N/A ASN 66.A N GLY 63.A O no hydrogen 2.903 N/A ASN 66.A ND2 VAL 60.A O no hydrogen 2.906 N/A LYS 67.A NZ ASP 254.A O no hydrogen 3.107 N/A GLU 70.A N GLU 70.A OE1 no hydrogen 2.756 N/A ARG 72.A N GLU 68.A O no hydrogen 2.970 N/A ARG 72.A NE GLU 52.A OE1 no hydrogen 3.275 N/A ARG 72.A NE GLU 52.A OE2 no hydrogen 2.731 N/A ARG 72.A NH1 LYS 67.A O no hydrogen 2.705 N/A ARG 72.A NH2 GLU 52.A OE1 no hydrogen 2.808 N/A ARG 72.A NH2 GLU 52.A OE2 no hydrogen 3.520 N/A ILE 73.A N ALA 69.A O no hydrogen 2.892 N/A PHE 74.A N GLU 70.A O no hydrogen 2.938 N/A HIS 75.A N VAL 71.A O no hydrogen 2.869 N/A CYS 76.A N ARG 72.A O no hydrogen 2.983 N/A CYS 76.A SG ARG 72.A O no hydrogen 3.451 N/A CYS 77.A N ILE 73.A O no hydrogen 2.873 N/A CYS 77.A SG ILE 73.A O no hydrogen 3.397 N/A GLN 78.A N PHE 74.A O no hydrogen 2.976 N/A GLN 78.A NE2 ALA 256.A O no hydrogen 2.998 N/A CYS 79.A N HIS 75.A O no hydrogen 2.943 N/A CYS 79.A SG HIS 75.A NE2 no hydrogen 3.641 N/A CYS 79.A SG HIS 75.A O no hydrogen 3.465 N/A THR 80.A N CYS 76.A O no hydrogen 3.101 N/A THR 80.A OG1 CYS 76.A O no hydrogen 2.936 N/A SER 81.A N CYS 77.A O no hydrogen 3.032 N/A SER 81.A OG CYS 77.A O no hydrogen 3.345 N/A VAL 82.A N GLN 78.A O no hydrogen 2.887 N/A GLU 83.A N.A CYS 79.A O no hydrogen 3.084 N/A GLU 83.A N.B CYS 79.A O no hydrogen 3.096 N/A THR 84.A N THR 80.A O no hydrogen 2.946 N/A THR 84.A OG1 THR 80.A O no hydrogen 3.013 N/A VAL 85.A N SER 81.A O no hydrogen 2.808 N/A THR 86.A N VAL 82.A O no hydrogen 3.132 N/A THR 86.A OG1 VAL 82.A O no hydrogen 3.047 N/A GLU 87.A N GLU 83.A O.A no hydrogen 3.011 N/A GLU 87.A N GLU 83.A O.B no hydrogen 3.014 N/A LEU 88.A N THR 84.A O no hydrogen 2.847 N/A THR 89.A N VAL 85.A O no hydrogen 2.966 N/A THR 89.A OG1 VAL 85.A O no hydrogen 2.823 N/A GLU 90.A N THR 86.A O no hydrogen 3.296 N/A PHE 91.A N GLU 87.A O no hydrogen 2.934 N/A ALA 92.A N LEU 88.A O no hydrogen 2.946 N/A LYS 93.A N GLU 90.A O no hydrogen 3.164 N/A LYS 93.A NZ GLU 90.A OE1 no hydrogen 2.784 N/A ALA 94.A N PHE 91.A O no hydrogen 2.897 N/A ILE 95.A N ALA 92.A O no hydrogen 3.040 N/A PHE 98.A N ILE 95.A O no hydrogen 2.980 N/A ASN 100.A N GLY 97.A O no hydrogen 3.151 N/A LEU 101.A N PHE 98.A O no hydrogen 3.091 N/A ASN 104.A N ASP 102.A OD2 no hydrogen 2.865 N/A GLN 106.A N ASP 102.A O no hydrogen 3.035 N/A GLN 106.A NE2 LEU 101.A O no hydrogen 2.901 N/A VAL 107.A N LEU 103.A O no hydrogen 2.947 N/A THR 108.A N ASN 104.A O no hydrogen 2.984 N/A THR 108.A OG1 ASN 104.A O no hydrogen 3.036 N/A LEU 109.A N ASP 105.A O no hydrogen 2.898 N/A LEU 110.A N GLN 106.A O no hydrogen 3.020 N/A LYS 111.A N VAL 107.A O no hydrogen 2.808 N/A LYS 111.A NZ ILE 264.A O no hydrogen 2.869 N/A LYS 111.A NZ ARG 266.A O no hydrogen 2.681 N/A TYR 112.A N THR 108.A O no hydrogen 3.178 N/A TYR 112.A OH MET 268.A O no hydrogen 2.915 N/A GLY 113.A N LEU 109.A O no hydrogen 2.890 N/A VAL 114.A N LEU 110.A O no hydrogen 2.912 N/A ALA 117.A N GLY 113.A O no hydrogen 2.964 N/A ILE 118.A N VAL 114.A O no hydrogen 2.735 N/A PHE 119.A N TYR 115.A O no hydrogen 2.985 N/A ALA 120.A N GLU 116.A O no hydrogen 3.021 N/A MET 121.A N ALA 117.A O no hydrogen 2.936 N/A LEU 122.A N ILE 118.A O no hydrogen 2.826 N/A SER 123.A N ALA 120.A O no hydrogen 3.257 N/A SER 123.A OG PHE 119.A O no hydrogen 3.412 N/A SER 123.A OG ALA 120.A O no hydrogen 3.146 N/A SER 124.A N MET 121.A O no hydrogen 2.938 N/A VAL 125.A N LEU 122.A O no hydrogen 2.974 N/A MET 126.A N SER 123.A O no hydrogen 3.128 N/A ASN 127.A N GLY 130.A O no hydrogen 2.948 N/A LYS 128.A NZ ASP 129.A OD2 no hydrogen 3.326 N/A ASP 129.A N ASN 127.A OD1 no hydrogen 2.863 N/A GLY 130.A N ASN 127.A O no hydrogen 3.370 N/A GLY 130.A N ASN 127.A OD1 no hydrogen 3.056 N/A MET 131.A N ILE 140.A O no hydrogen 2.939 N/A LEU 132.A N VAL 125.A O no hydrogen 2.935 N/A VAL 133.A N GLY 138.A O no hydrogen 2.844 N/A ASN 137.A N ALA 134.A O no hydrogen 3.014 N/A ASN 137.A ND2 ALA 134.A O no hydrogen 3.048 N/A GLY 138.A N VAL 133.A O no hydrogen 2.960 N/A PHE 139.A N PHE 40.A O.A no hydrogen 2.959 N/A PHE 139.A N PHE 40.A O.B no hydrogen 2.700 N/A ILE 140.A N MET 131.A O no hydrogen 2.917 N/A THR 141.A N ILE 42.A O no hydrogen 2.942 N/A ARG 142.A N ASP 129.A O no hydrogen 2.865 N/A ARG 142.A NE GLU 157.A OE1 no hydrogen 3.010 N/A ARG 142.A NE GLU 157.A OE2 no hydrogen 3.263 N/A ARG 142.A NH1 LYS 128.A O no hydrogen 3.235 N/A ARG 142.A NH2 GLU 157.A OE2 no hydrogen 3.085 N/A PHE 144.A N THR 141.A OG1 no hydrogen 2.989 N/A LEU 145.A N THR 141.A O no hydrogen 3.124 N/A LYS 146.A N ARG 142.A O no hydrogen 3.022 N/A LYS 146.A NZ GLU 143.A OE2 no hydrogen 3.074 N/A SER 147.A N PHE 144.A O no hydrogen 2.942 N/A SER 147.A OG PHE 144.A O no hydrogen 2.683 N/A LEU 148.A N LEU 145.A O no hydrogen 3.365 N/A ARG 149.A N GLU 70.A OE2 no hydrogen 2.919 N/A ARG 149.A NE GLU 68.A OE2 no hydrogen 2.720 N/A ARG 149.A NH1 LYS 150.A O no hydrogen 3.001 N/A ARG 149.A NH1 GLU 252.A OE2 no hydrogen 2.894 N/A ARG 149.A NH2 GLU 68.A OE1 no hydrogen 3.023 N/A ARG 149.A NH2 GLU 68.A OE2 no hydrogen 3.468 N/A ARG 149.A NH2 GLU 252.A OE1 no hydrogen 2.741 N/A ARG 149.A NH2 GLU 252.A OE2 no hydrogen 3.509 N/A LYS 150.A NZ ASP 154.A OD1 no hydrogen 3.126 N/A PHE 152.A N ARG 149.A O no hydrogen 2.889 N/A CYS 153.A N ARG 149.A O no hydrogen 3.408 N/A CYS 153.A SG ASP 154.A OD1 no hydrogen 3.562 N/A ASP 154.A N PRO 151.A O no hydrogen 3.044 N/A ILE 155.A N PHE 152.A O no hydrogen 3.347 N/A LYS 159.A N MET 156.A O no hydrogen 2.866 N/A LYS 159.A NZ ILE 155.A O no hydrogen 2.846 N/A LYS 159.A NZ HIS 241.A ND1 no hydrogen 2.858 N/A PHE 160.A N MET 156.A O no hydrogen 2.988 N/A ASP 161.A N GLU 157.A O no hydrogen 2.970 N/A PHE 162.A N PRO 158.A O no hydrogen 2.996 N/A ALA 163.A N LYS 159.A O no hydrogen 2.897 N/A MET 164.A N PHE 160.A O no hydrogen 2.882 N/A PHE 166.A N PHE 162.A O no hydrogen 2.928 N/A ASN 167.A N ALA 163.A O no hydrogen 2.765 N/A ASN 167.A ND2 SER 123.A O no hydrogen 2.947 N/A ALA 168.A N MET 164.A O no hydrogen 3.242 N/A ALA 168.A N LYS 165.A O no hydrogen 3.198 N/A LEU 169.A N PHE 166.A O no hydrogen 3.079 N/A GLU 170.A N ASN 167.A O no hydrogen 2.974 N/A ASP 172.A N ASP 175.A OD2 no hydrogen 2.841 N/A SER 174.A OG ASP 172.A OD1 no hydrogen 2.539 N/A SER 174.A OG HIS 212.A NE2 no hydrogen 2.900 N/A ASP 175.A N ASP 172.A O no hydrogen 2.958 N/A ASP 175.A N ASP 172.A OD1 no hydrogen 3.187 N/A ILE 176.A N ASP 172.A O no hydrogen 2.913 N/A SER 177.A N ASP 173.A O.A no hydrogen 2.914 N/A SER 177.A N ASP 173.A O.B no hydrogen 2.907 N/A SER 177.A OG ASP 173.A O.A no hydrogen 3.241 N/A SER 177.A OG ASP 173.A O.B no hydrogen 3.069 N/A SER 177.A OG SER 174.A O no hydrogen 3.023 N/A PHE 179.A N ASP 175.A O no hydrogen 2.979 N/A VAL 180.A N ILE 176.A O no hydrogen 2.860 N/A ALA 181.A N SER 177.A O no hydrogen 3.032 N/A ALA 182.A N LEU 178.A O no hydrogen 2.890 N/A ILE 183.A N PHE 179.A O no hydrogen 2.918 N/A ILE 184.A N VAL 180.A O no hydrogen 3.134 N/A CYS 185.A N ALA 181.A O no hydrogen 3.224 N/A CYS 185.A N ALA 182.A O no hydrogen 3.155 N/A CYS 185.A SG ALA 181.A O no hydrogen 3.380 N/A CYS 186.A SG ILE 183.A O no hydrogen 3.408 N/A GLY 187.A N GLN 202.A OE1 no hydrogen 2.903 N/A ARG 189.A NH1 GLU 116.A OE2 no hydrogen 2.888 N/A ARG 189.A NH2 GLU 116.A OE1 no hydrogen 2.898 N/A ARG 189.A NH2 ILE 183.A O no hydrogen 3.147 N/A LEU 193.A N ASP 105.A OD1 no hydrogen 2.863 N/A ASN 194.A N ASP 105.A OD2 no hydrogen 2.937 N/A ASN 194.A ND2 HIS 197.A ND1 no hydrogen 2.742 N/A HIS 197.A N ASN 194.A OD1 no hydrogen 3.140 N/A ILE 198.A N ASN 194.A O no hydrogen 3.128 N/A GLU 199.A N VAL 195.A O no hydrogen 2.775 N/A LYS 200.A N.A GLY 196.A O no hydrogen 3.137 N/A LYS 200.A N.B GLY 196.A O no hydrogen 3.121 N/A LYS 200.A NZ.B GLY 196.A O no hydrogen 3.064 N/A MET 201.A N.A HIS 197.A O no hydrogen 2.908 N/A MET 201.A N.B HIS 197.A O no hydrogen 3.001 N/A GLN 202.A N ILE 198.A O no hydrogen 2.777 N/A GLU 203.A N.A GLU 199.A O no hydrogen 2.851 N/A GLU 203.A N.B GLU 199.A O no hydrogen 2.853 N/A GLY 204.A N LYS 200.A O.A no hydrogen 3.085 N/A GLY 204.A N LYS 200.A O.B no hydrogen 2.917 N/A ILE 205.A N.A MET 201.A O.A no hydrogen 3.080 N/A ILE 205.A N.A MET 201.A O.B no hydrogen 3.012 N/A ILE 205.A N.B MET 201.A O.A no hydrogen 3.080 N/A ILE 205.A N.B MET 201.A O.B no hydrogen 3.012 N/A VAL 206.A N GLN 202.A O no hydrogen 2.873 N/A HIS 207.A N GLU 203.A O.A no hydrogen 2.984 N/A HIS 207.A N GLU 203.A O.B no hydrogen 3.010 N/A VAL 208.A N GLY 204.A O no hydrogen 3.103 N/A LEU 209.A N ILE 205.A O.A no hydrogen 2.931 N/A LEU 209.A N ILE 205.A O.B no hydrogen 2.869 N/A ARG 210.A N.A VAL 206.A O no hydrogen 2.820 N/A ARG 210.A N.B VAL 206.A O no hydrogen 2.806 N/A LEU 211.A N HIS 207.A O no hydrogen 2.982 N/A HIS 212.A N VAL 208.A O no hydrogen 2.943 N/A HIS 212.A NE2 SER 174.A OG no hydrogen 2.900 N/A LEU 213.A N LEU 209.A O no hydrogen 2.901 N/A GLN 214.A N ARG 210.A O.A no hydrogen 3.053 N/A GLN 214.A N ARG 210.A O.B no hydrogen 3.055 N/A SER 215.A N.A LEU 211.A O no hydrogen 3.102 N/A SER 215.A N.B LEU 211.A O no hydrogen 3.097 N/A SER 215.A N.B HIS 212.A O no hydrogen 3.156 N/A SER 215.A OG.A LEU 211.A O no hydrogen 3.412 N/A ASN 216.A N HIS 212.A O no hydrogen 2.763 N/A ASN 216.A ND2 ASP 172.A OD1 no hydrogen 3.554 N/A ASN 216.A ND2 ASP 172.A OD2 no hydrogen 3.025 N/A ASN 216.A ND2 ASP 175.A OD1 no hydrogen 2.897 N/A HIS 217.A N LEU 213.A O no hydrogen 2.865 N/A HIS 217.A NE2 ASP 175.A OD2 no hydrogen 2.668 N/A ASP 220.A N HIS 217.A O no hydrogen 3.168 N/A LEU 223.A N ASP 220.A O no hydrogen 3.119 N/A LYS 226.A N PHE 222.A O no hydrogen 2.977 N/A LYS 226.A NZ ASP 220.A OD1 no hydrogen 3.146 N/A LYS 226.A NZ ASP 220.A OD2 no hydrogen 2.901 N/A LEU 227.A N LEU 223.A O no hydrogen 2.966 N/A LEU 228.A N PHE 224.A O no hydrogen 2.946 N/A GLN 229.A N PRO 225.A O no hydrogen 3.001 N/A LYS 230.A N LYS 226.A O no hydrogen 2.925 N/A MET 231.A N LEU 227.A O no hydrogen 2.962 N/A ALA 232.A N LEU 228.A O no hydrogen 3.273 N/A ASP 233.A N GLN 229.A O no hydrogen 2.852 N/A LEU 234.A N LYS 230.A O no hydrogen 2.860 N/A ARG 235.A N MET 231.A O no hydrogen 3.055 N/A ARG 235.A NH1 ASP 188.A OD1 no hydrogen 3.568 N/A ARG 235.A NH1 ASP 188.A OD2 no hydrogen 2.817 N/A ARG 235.A NH2 ASP 188.A OD1 no hydrogen 2.896 N/A ARG 235.A NH2 ASP 188.A OD2 no hydrogen 3.516 N/A GLN 236.A N.A ALA 232.A O no hydrogen 3.176 N/A GLN 236.A N.B ALA 232.A O no hydrogen 3.161 N/A GLN 236.A NE2.A GLU 240.A OE2 no hydrogen 3.104 N/A GLN 236.A NE2.B GLU 240.A OE2 no hydrogen 2.884 N/A LEU 237.A N ASP 233.A O no hydrogen 2.887 N/A VAL 238.A N LEU 234.A O no hydrogen 2.876 N/A THR 239.A N ARG 235.A O no hydrogen 2.968 N/A THR 239.A OG1 ARG 235.A O no hydrogen 3.034 N/A GLU 240.A N GLN 236.A O.A no hydrogen 3.049 N/A GLU 240.A N GLN 236.A O.B no hydrogen 2.980 N/A HIS 241.A N LEU 237.A O no hydrogen 2.857 N/A ALA 242.A N VAL 238.A O no hydrogen 2.836 N/A GLN 243.A N THR 239.A O no hydrogen 3.127 N/A LEU 244.A N GLU 240.A O no hydrogen 3.087 N/A VAL 245.A N HIS 241.A O no hydrogen 2.889 N/A GLN 246.A N ALA 242.A O no hydrogen 2.978 N/A ILE 247.A N GLN 243.A O no hydrogen 3.068 N/A ILE 248.A N LEU 244.A O no hydrogen 2.929 N/A LYS 249.A N VAL 245.A O no hydrogen 2.839 N/A LYS 250.A N GLN 246.A O no hydrogen 2.920 N/A THR 251.A N ILE 247.A O no hydrogen 2.953 N/A THR 251.A N ILE 248.A O no hydrogen 3.334 N/A THR 251.A OG1 ILE 247.A O no hydrogen 2.684 N/A GLU 252.A N ILE 248.A O no hydrogen 2.799 N/A ALA 255.A N GLU 252.A O no hydrogen 3.050 N/A HIS 258.A N GLN 78.A OE1 no hydrogen 2.799 N/A LEU 260.A N HIS 258.A ND1 no hydrogen 2.992 N/A GLN 262.A N HIS 258.A O no hydrogen 2.956 N/A GLU 263.A N PRO 259.A O no hydrogen 3.081 N/A ILE 264.A N LEU 260.A O no hydrogen 3.093 N/A TYR 265.A N LEU 261.A O no hydrogen 2.904 N/A ARG 266.A N GLU 263.A O no hydrogen 3.227 N/A MET 268.A N TYR 265.A O no hydrogen 3.085 N/A