Finding intermodel H-bonds
Finding intramodel H-bonds
Constraints relaxed by 0.4 angstroms and 20 degrees
Models used:
	#0 2zon_A.cif

H-bonds (donor, acceptor, hydrogen, D..A dist, D-H..A dist):
ASP 3.A N      ASP 1.A OD2    no hydrogen  3.325  N/A
LYS 4.A N      ASP 1.A O      no hydrogen  2.898  N/A
LEU 5.A N      ALA 2.A O      no hydrogen  3.156  N/A
HIS 7.A ND1    LEU 5.A O      no hydrogen  3.043  N/A
THR 8.A N      VAL 31.A O     no hydrogen  2.775  N/A
VAL 10.A N     GLU 33.A O     no hydrogen  3.059  N/A
GLN 17.A N     ALA 14.A O     no hydrogen  3.224  N/A
HIS 19.A ND1   PRO 20.A O     no hydrogen  2.980  N/A
HIS 21.A ND1   HIS 19.A O     no hydrogen  2.912  N/A
HIS 21.A NE2   TYR 165.A OH   no hydrogen  2.624  N/A
GLN 23.A NE2   TYR 165.A O    no hydrogen  2.862  N/A
THR 25.A N     ARG 152.A O    no hydrogen  2.834  N/A
THR 25.A OG1   GLU 22.A OE1   no hydrogen  2.732  N/A
LYS 26.A NZ    GLU 22.A OE2   no hydrogen  2.718  N/A
LYS 26.A NZ    THR 25.A OG1   no hydrogen  3.420  N/A
SER 27.A N     THR 25.A OG1   no hydrogen  3.009  N/A
SER 27.A OG    GLY 28.A O     no hydrogen  2.798  N/A
LYS 30.A N     ASP 72.A OD1   no hydrogen  3.039  N/A
VAL 31.A N     PRO 6.A O      no hydrogen  2.952  N/A
VAL 32.A N     TYR 73.A O     no hydrogen  2.856  N/A
GLU 33.A N     THR 8.A O      no hydrogen  2.682  N/A
PHE 34.A N     GLN 75.A O     no hydrogen  2.902  N/A
MET 36.A N     THR 77.A O     no hydrogen  3.009  N/A
THR 37.A N     ASN 58.A OD1   no hydrogen  2.860  N/A
ILE 38.A N     VAL 79.A O     no hydrogen  2.844  N/A
GLU 39.A N     THR 56.A O     no hydrogen  2.892  N/A
GLU 40.A N     ASN 84.A OD1   no hydrogen  3.041  N/A
LYS 41.A N     ALA 54.A O     no hydrogen  3.008  N/A
LYS 41.A NZ    GLU 39.A OE1   no hydrogen  3.058  N/A
LYS 41.A NZ    GLY 59.A O     no hydrogen  2.772  N/A
LYS 42.A NZ    ASP 188.A OD1  no hydrogen  2.760  N/A
LYS 42.A NZ    ASP 188.A OD2  no hydrogen  3.161  N/A
LYS 42.A NZ    TYR 189.A O    no hydrogen  2.947  N/A
MET 43.A N     LEU 52.A O     no hydrogen  2.859  N/A
ILE 45.A N     THR 50.A O     no hydrogen  2.883  N/A
LYS 48.A N     ASP 46.A OD1   no hydrogen  2.837  N/A
THR 50.A N     ASP 46.A OD1   no hydrogen  2.974  N/A
THR 50.A OG1   ASP 46.A OD1   no hydrogen  3.285  N/A
THR 50.A OG1   ASP 46.A OD2   no hydrogen  2.738  N/A
THR 51.A OG1   ASP 188.A OD1  no hydrogen  2.687  N/A
LEU 52.A N     MET 43.A O     no hydrogen  2.801  N/A
GLN 53.A NE2   TYR 189.A O    no hydrogen  2.937  N/A
ALA 54.A N     LYS 41.A O     no hydrogen  2.913  N/A
MET 55.A N     SER 141.A O    no hydrogen  2.949  N/A
THR 56.A N     GLU 39.A O     no hydrogen  3.026  N/A
THR 56.A OG1   GLU 39.A O     no hydrogen  2.846  N/A
ASN 58.A N     THR 37.A O     no hydrogen  2.808  N/A
SER 60.A N     PHE 57.A O     no hydrogen  3.447  N/A
SER 60.A OG    PHE 57.A O     no hydrogen  3.563  N/A
SER 60.A OG    PRO 62.A O     no hydrogen  2.787  N/A
GLY 63.A N     SER 144.A O    no hydrogen  2.788  N/A
THR 65.A OG1   THR 170.A OG1  no hydrogen  2.742  N/A
LEU 66.A N     THR 146.A O    no hydrogen  3.026  N/A
VAL 67.A N     HIS 19.A NE2   no hydrogen  2.932  N/A
VAL 68.A N     MET 148.A O    no hydrogen  2.966  N/A
HIS 69.A N     ASP 72.A OD2   no hydrogen  2.870  N/A
HIS 69.A NE2   GLN 23.A O     no hydrogen  2.618  N/A
GLU 70.A N     LEU 150.A O    no hydrogen  2.804  N/A
GLY 71.A N     ALA 119.A O    no hydrogen  2.825  N/A
ASP 72.A N     HIS 69.A O     no hydrogen  2.881  N/A
TYR 73.A N     LYS 30.A O     no hydrogen  2.919  N/A
VAL 74.A N     PHE 117.A O    no hydrogen  2.777  N/A
GLN 75.A N     VAL 32.A O     no hydrogen  2.909  N/A
LEU 76.A N     LEU 115.A O    no hydrogen  2.823  N/A
THR 77.A N     PHE 34.A O     no hydrogen  2.851  N/A
THR 77.A OG1   THR 114.A OG1  no hydrogen  2.892  N/A
LEU 78.A N     ALA 113.A O    no hydrogen  2.808  N/A
VAL 79.A N     MET 36.A O     no hydrogen  2.872  N/A
ASN 80.A N     GLU 111.A O    no hydrogen  2.937  N/A
ASN 80.A ND2   MET 86.A O     no hydrogen  3.051  N/A
ASN 80.A ND2   VAL 107.A O    no hydrogen  2.845  N/A
ASN 84.A N     PRO 81.A O     no hydrogen  3.026  N/A
ASN 84.A ND2   ILE 38.A O     no hydrogen  3.059  N/A
ASN 84.A ND2   ASN 80.A OD1   no hydrogen  2.798  N/A
ALA 85.A N     GLU 40.A OE1   no hydrogen  2.749  N/A
MET 86.A N     GLU 40.A OE2   no hydrogen  2.894  N/A
HIS 88.A N     VAL 107.A O    no hydrogen  3.029  N/A
HIS 88.A NE2   GLU 40.A OE2   no hydrogen  2.701  N/A
ASN 89.A ND2   ALA 102.A O    no hydrogen  3.341  N/A
ASN 89.A ND2   ALA 130.A O    no hydrogen  2.988  N/A
VAL 90.A N     THR 105.A OG1  no hydrogen  2.953  N/A
ASP 91.A N     HIS 128.A O    no hydrogen  2.802  N/A
PHE 92.A N     GLY 100.A O    no hydrogen  2.831  N/A
HIS 93.A N     VAL 126.A O    no hydrogen  2.969  N/A
ALA 95.A N     PHE 92.A O     no hydrogen  3.076  N/A
GLY 100.A N    GLY 97.A O     no hydrogen  2.858  N/A
GLY 101.A N    ALA 98.A O     no hydrogen  2.974  N/A
ALA 102.A N    LEU 99.A O     no hydrogen  3.351  N/A
LYS 103.A N    ALA 98.A O     no hydrogen  3.267  N/A
LEU 104.A N    GLY 101.A O    no hydrogen  2.966  N/A
THR 105.A N    ALA 102.A O    no hydrogen  3.499  N/A
THR 105.A OG1  VAL 90.A O     no hydrogen  3.257  N/A
THR 105.A OG1  GLY 101.A O    no hydrogen  2.790  N/A
THR 105.A OG1  ALA 102.A O    no hydrogen  3.570  N/A
VAL 107.A N    HIS 88.A O     no hydrogen  2.959  N/A
ASN 108.A N    GLU 111.A OE1  no hydrogen  2.856  N/A
GLY 110.A N    ASN 80.A O     no hydrogen  2.690  N/A
GLU 111.A N    ASN 108.A O    no hydrogen  2.888  N/A
ALA 113.A N    LEU 78.A O     no hydrogen  3.058  N/A
THR 114.A OG1  THR 77.A OG1   no hydrogen  2.892  N/A
LEU 115.A N    LEU 76.A O     no hydrogen  2.960  N/A
ARG 116.A NH1  ASP 3.A OD1    no hydrogen  3.062  N/A
PHE 117.A N    VAL 74.A O     no hydrogen  2.958  N/A
LYS 118.A NZ   TYR 73.A OH    no hydrogen  3.475  N/A
ALA 119.A N    ASP 72.A O     no hydrogen  2.911  N/A
GLY 123.A N    VAL 149.A O    no hydrogen  2.737  N/A
THR 124.A N    GLY 261.A O    no hydrogen  2.822  N/A
THR 124.A OG1  GLY 261.A O    no hydrogen  3.364  N/A
THR 124.A OG1  ALA 281.A O    no hydrogen  2.883  N/A
PHE 125.A N    LEU 147.A O    no hydrogen  2.764  N/A
TYR 127.A N    GLY 145.A O    no hydrogen  2.881  N/A
TYR 127.A OH   PRO 64.A O     no hydrogen  2.707  N/A
HIS 128.A N    ASP 91.A O     no hydrogen  2.942  N/A
HIS 128.A ND1  CYS 129.A O    no hydrogen  2.835  N/A
CYS 129.A N    MET 143.A O    no hydrogen  3.074  N/A
CYS 129.A SG   HIS 88.A ND1   no hydrogen  3.851  N/A
CYS 129.A SG   ASN 89.A O     no hydrogen  3.588  N/A
CYS 129.A SG   ASN 89.A OD1   no hydrogen  3.758  N/A
CYS 129.A SG   HIS 138.A ND1  no hydrogen  3.643  N/A
ALA 130.A N    ASN 89.A OD1   no hydrogen  2.707  N/A
MET 134.A N    PRO 131.A O    no hydrogen  2.976  N/A
HIS 138.A N    MET 134.A O    no hydrogen  3.451  N/A
VAL 139.A N    VAL 135.A O    no hydrogen  3.241  N/A
VAL 140.A N    PRO 136.A O    no hydrogen  2.938  N/A
SER 141.A N    TRP 137.A O    no hydrogen  3.040  N/A
SER 141.A OG   TRP 137.A O    no hydrogen  2.717  N/A
GLY 142.A N    VAL 139.A O    no hydrogen  3.057  N/A
MET 143.A N    HIS 138.A O    no hydrogen  3.130  N/A
SER 144.A N    GLY 142.A O    no hydrogen  3.054  N/A
GLY 145.A N    TYR 127.A O    no hydrogen  3.001  N/A
LEU 147.A N    PHE 125.A O    no hydrogen  2.721  N/A
MET 148.A N    LEU 66.A O     no hydrogen  2.697  N/A
VAL 149.A N    GLY 123.A O    no hydrogen  2.795  N/A
LEU 150.A N    VAL 68.A O     no hydrogen  2.791  N/A
ARG 152.A NE   GLU 70.A O     no hydrogen  3.370  N/A
ARG 152.A NH1  SER 27.A O     no hydrogen  2.936  N/A
ARG 152.A NH2  GLU 70.A O     no hydrogen  2.920  N/A
ARG 152.A NH2  ASP 72.A OD1   no hydrogen  2.950  N/A
GLY 154.A N    PRO 151.A O    no hydrogen  2.916  N/A
LYS 156.A NZ   ASP 153.A O    no hydrogen  3.154  N/A
ASP 157.A N    LYS 161.A O    no hydrogen  2.813  N/A
GLN 159.A N    ASP 157.A OD1  no hydrogen  2.877  N/A
GLY 160.A N    ASP 157.A O    no hydrogen  2.924  N/A
LYS 161.A N    ASP 157.A OD1  no hydrogen  2.903  N/A
LEU 163.A N    LEU 155.A O    no hydrogen  2.946  N/A
TYR 165.A N    GLN 23.A OE1   no hydrogen  3.127  N/A
TYR 165.A OH   HIS 21.A NE2   no hydrogen  2.624  N/A
ASP 166.A N    THR 233.A O    no hydrogen  2.716  N/A
ARG 167.A N    THR 233.A O    no hydrogen  3.399  N/A
ARG 167.A NE   THR 227.A O    no hydrogen  2.809  N/A
TYR 169.A N    LEU 235.A O    no hydrogen  2.858  N/A
TYR 169.A OH   THR 227.A O    no hydrogen  2.709  N/A
THR 170.A N    PRO 16.A O     no hydrogen  2.843  N/A
THR 170.A OG1  THR 65.A OG1   no hydrogen  2.742  N/A
ILE 171.A N    ILE 237.A O    no hydrogen  2.804  N/A
GLY 172.A N    ASN 214.A OD1  no hydrogen  2.872  N/A
GLU 173.A N    SER 239.A O    no hydrogen  2.947  N/A
PHE 174.A N    VAL 212.A O    no hydrogen  2.821  N/A
LEU 176.A N    HIS 210.A O    no hydrogen  2.861  N/A
TYR 177.A OH   ASP 175.A OD2  no hydrogen  2.568  N/A
ILE 178.A N    SER 209.A OG   no hydrogen  2.998  N/A
GLY 181.A N    LYS 185.A O    no hydrogen  2.800  N/A
GLY 184.A N    GLY 181.A O    no hydrogen  2.887  N/A
LYS 185.A N    ASP 183.A OD2  no hydrogen  3.101  N/A
LYS 187.A N    PRO 179.A O    no hydrogen  2.942  N/A
LYS 187.A NZ   ASP 198.A OD2  no hydrogen  2.826  N/A
TYR 189.A OH   ASP 198.A OD2  no hydrogen  2.560  N/A
GLU 194.A N    THR 191.A OG1  no hydrogen  3.199  N/A
SER 195.A N    LEU 192.A O    no hydrogen  3.030  N/A
SER 195.A OG   LEU 192.A O    no hydrogen  2.583  N/A
TYR 196.A N    ALA 193.A O    no hydrogen  3.128  N/A
THR 199.A N    SER 195.A O    no hydrogen  3.169  N/A
THR 199.A OG1  SER 195.A O    no hydrogen  2.614  N/A
VAL 200.A N    TYR 196.A O    no hydrogen  2.875  N/A
GLN 201.A N    GLY 197.A O    no hydrogen  3.377  N/A
VAL 202.A N    ASP 198.A O    no hydrogen  3.374  N/A
MET 203.A N    THR 199.A O    no hydrogen  2.817  N/A
ARG 204.A N    VAL 200.A O    no hydrogen  2.918  N/A
THR 205.A N    VAL 202.A O    no hydrogen  3.041  N/A
THR 205.A OG1  VAL 202.A O    no hydrogen  2.653  N/A
LEU 206.A N    MET 203.A O    no hydrogen  2.852  N/A
THR 207.A N    THR 205.A OG1  no hydrogen  3.296  N/A
THR 207.A OG1  THR 205.A O    no hydrogen  3.138  N/A
SER 209.A N    LEU 176.A O    no hydrogen  2.869  N/A
SER 209.A OG   LEU 176.A O    no hydrogen  3.304  N/A
SER 209.A OG   HIS 210.A ND1  no hydrogen  2.783  N/A
HIS 210.A ND1  SER 209.A OG   no hydrogen  2.783  N/A
HIS 210.A NE2  ASP 46.A OD2   no hydrogen  2.991  N/A
ILE 211.A N    LEU 307.A O    no hydrogen  2.888  N/A
VAL 212.A N    PHE 174.A O    no hydrogen  2.890  N/A
ASN 214.A N    GLY 172.A O    no hydrogen  2.841  N/A
ASN 214.A ND2  THR 170.A O    no hydrogen  3.363  N/A
VAL 217.A N    ILE 45.A O     no hydrogen  2.923  N/A
ALA 219.A N    LYS 216.A O    no hydrogen  3.046  N/A
THR 221.A N    GLY 218.A O    no hydrogen  3.122  N/A
THR 221.A OG1  GLY 218.A O    no hydrogen  2.688  N/A
ASN 224.A N    THR 221.A O    no hydrogen  2.964  N/A
ALA 225.A N    GLY 222.A O    no hydrogen  3.144  N/A
LEU 226.A N    HIS 312.A O    no hydrogen  2.885  N/A
THR 227.A N    TYR 169.A OH   no hydrogen  3.124  N/A
THR 227.A OG1  TYR 169.A OH   no hydrogen  3.397  N/A
ALA 228.A N    LYS 314.A O    no hydrogen  3.123  N/A
LYS 229.A N    GLU 232.A OE1  no hydrogen  3.042  N/A
VAL 230.A N    GLU 316.A O    no hydrogen  2.782  N/A
GLY 231.A N    PHE 288.A O    no hydrogen  2.816  N/A
GLU 232.A N    LYS 229.A O    no hydrogen  2.997  N/A
THR 233.A N    ASP 166.A OD2  no hydrogen  2.829  N/A
THR 233.A OG1  THR 287.A OG1  no hydrogen  2.804  N/A
VAL 234.A N    TYR 286.A O    no hydrogen  2.861  N/A
LEU 235.A N    ARG 167.A O    no hydrogen  2.894  N/A
LEU 236.A N    ALA 284.A O    no hydrogen  2.735  N/A
ILE 237.A N    TYR 169.A O    no hydrogen  2.917  N/A
HIS 238.A N    GLY 282.A O    no hydrogen  3.020  N/A
HIS 238.A ND1  TYR 296.A OH   no hydrogen  2.651  N/A
HIS 238.A NE2  GLU 173.A OE1  no hydrogen  2.851  N/A
SER 239.A N    ILE 171.A O    no hydrogen  2.942  N/A
GLN 240.A N    SER 280.A O    no hydrogen  3.084  N/A
GLN 240.A NE2  ASP 175.A OD1  no hydrogen  3.054  N/A
ASN 242.A N    GLN 240.A OE1  no hydrogen  2.845  N/A
ASN 242.A ND2  ASP 175.A OD2  no hydrogen  2.872  N/A
ARG 243.A N    GLN 240.A OE1  no hydrogen  2.992  N/A
ARG 243.A NH1  GLU 303.A OE1  no hydrogen  3.041  N/A
ARG 243.A NH1  GLU 303.A OE2  no hydrogen  3.234  N/A
ARG 243.A NH2  GLU 303.A OE2  no hydrogen  2.874  N/A
THR 245.A N    ILE 276.A O    no hydrogen  2.962  N/A
THR 245.A OG1  GLU 173.A OE1  no hydrogen  2.647  N/A
THR 245.A OG1  GLU 173.A OE2  no hydrogen  3.197  N/A
ARG 246.A NH1  ASN 298.A OD1  no hydrogen  2.867  N/A
ARG 246.A NH1  GLU 303.A OE1  no hydrogen  3.335  N/A
HIS 248.A N    LEU 297.A O    no hydrogen  2.838  N/A
HIS 248.A ND1  THR 273.A OG1  no hydrogen  3.187  N/A
ILE 250.A N    ALA 295.A O    no hydrogen  2.746  N/A
GLY 252.A N    LEU 249.A O    no hydrogen  2.925  N/A
GLY 254.A N    LEU 271.A O    no hydrogen  2.875  N/A
ASP 255.A N    LEU 285.A O    no hydrogen  2.798  N/A
TRP 256.A N    LEU 285.A O    no hydrogen  3.404  N/A
VAL 257.A N    GLN 268.A O    no hydrogen  2.743  N/A
TRP 258.A N    ALA 283.A O    no hydrogen  2.858  N/A
GLY 261.A N    TRP 258.A O    no hydrogen  2.888  N/A
LYS 262.A NZ   THR 124.A O    no hydrogen  2.574  N/A
LYS 262.A NZ   THR 260.A O    no hydrogen  2.845  N/A
LYS 262.A NZ   GLY 261.A O    no hydrogen  3.236  N/A
ASN 265.A N    LYS 262.A O    no hydrogen  3.088  N/A
ASN 265.A ND2  LYS 262.A O    no hydrogen  3.178  N/A
GLN 268.A N    VAL 257.A O    no hydrogen  2.887  N/A
ARG 269.A NE   ASP 270.A OD2  no hydrogen  2.822  N/A
ARG 269.A NH2  ASP 270.A OD1  no hydrogen  3.120  N/A
ARG 269.A NH2  ASP 270.A OD2  no hydrogen  3.373  N/A
ASP 270.A N    ASP 255.A O    no hydrogen  3.340  N/A
LEU 271.A N    GLY 254.A O    no hydrogen  2.999  N/A
THR 273.A OG1  HIS 248.A ND1  no hydrogen  3.187  N/A
TRP 274.A N    PRO 247.A O    no hydrogen  3.044  N/A
PHE 275.A N    GLU 259.A OE1  no hydrogen  3.003  N/A
ILE 276.A N    THR 245.A O    no hydrogen  2.860  N/A
ARG 277.A NH1  GLU 259.A OE2  no hydrogen  3.365  N/A
ARG 277.A NH1  PHE 275.A O    no hydrogen  2.862  N/A
ARG 277.A NH2  GLU 259.A OE2  no hydrogen  2.869  N/A
GLY 278.A N    ASP 244.A OD1  no hydrogen  2.870  N/A
GLY 279.A N    GLN 240.A O    no hydrogen  2.712  N/A
SER 280.A N    GLN 240.A O    no hydrogen  3.220  N/A
SER 280.A OG   ARG 277.A O    no hydrogen  2.639  N/A
GLY 282.A N    HIS 238.A O    no hydrogen  2.960  N/A
ALA 283.A N    TRP 258.A O    no hydrogen  3.124  N/A
ALA 284.A N    LEU 236.A O    no hydrogen  3.006  N/A
LEU 285.A N    TRP 256.A O    no hydrogen  2.800  N/A
TYR 286.A N    VAL 234.A O    no hydrogen  3.024  N/A
THR 287.A N    ASP 255.A OD2  no hydrogen  2.982  N/A
THR 287.A OG1  THR 233.A OG1  no hydrogen  2.804  N/A
PHE 288.A N    GLU 232.A O    no hydrogen  3.104  N/A
GLN 290.A NE2  ASN 320.A O    no hydrogen  3.080  N/A
GLY 292.A N    VAL 315.A O    no hydrogen  2.807  N/A
TYR 294.A N    ILE 313.A O    no hydrogen  2.737  N/A
TYR 294.A OH   GLN 290.A O    no hydrogen  2.607  N/A
TYR 296.A N    GLY 311.A O    no hydrogen  2.786  N/A
TYR 296.A OH   HIS 238.A ND1  no hydrogen  2.651  N/A
LEU 297.A N    HIS 248.A O    no hydrogen  2.935  N/A
ASN 298.A N    ALA 309.A O    no hydrogen  3.050  N/A
ASN 298.A ND2  GLU 173.A OE2  no hydrogen  2.938  N/A
ASN 298.A ND2  GLU 303.A OE1  no hydrogen  2.767  N/A
HIS 299.A N    ARG 246.A O    no hydrogen  2.839  N/A
HIS 299.A ND1  HIS 299.A O    no hydrogen  2.677  N/A
ASN 300.A N    ASN 298.A OD1  no hydrogen  2.883  N/A
GLU 303.A N    ASN 300.A OD1  no hydrogen  3.304  N/A
ALA 304.A N    ASN 300.A O    no hydrogen  2.945  N/A
PHE 305.A N    LEU 301.A O    no hydrogen  2.805  N/A
GLU 306.A N    ILE 302.A O    no hydrogen  2.843  N/A
LEU 307.A N    ILE 302.A O    no hydrogen  3.018  N/A
GLY 308.A N    ALA 304.A O    no hydrogen  3.236  N/A
ALA 309.A N    GLU 303.A O    no hydrogen  2.984  N/A
ALA 310.A N    GLY 308.A O    no hydrogen  2.924  N/A
GLY 311.A N    TYR 296.A O    no hydrogen  2.735  N/A
HIS 312.A N    LEU 220.A O    no hydrogen  2.817  N/A
ILE 313.A N    TYR 294.A O    no hydrogen  2.976  N/A
LYS 314.A N    LEU 226.A O    no hydrogen  2.831  N/A
VAL 315.A N    GLY 292.A O    no hydrogen  2.868  N/A
GLU 316.A N    ALA 228.A O    no hydrogen  3.059  N/A
TRP 319.A NE1  MET 324.A O    no hydrogen  3.006  N/A
ASN 320.A N    GLN 290.A OE1  no hydrogen  2.827  N/A
LEU 323.A N    ASN 320.A OD1  no hydrogen  3.047  N/A
MET 324.A N    ASN 320.A O    no hydrogen  3.299  N/A