C -----------------------------------
C   ICONC_PDB
C     code:
C      1         covalent bonds IC1,IC2,IC3,IC4
C      2         salt bridges   IC5 ( I has an excess of negative charge)
C      3         salt bridges   IC6 ( I has an excess of positive charge)
C      4         hydrogen bond  IC7 ( I acts as donor)
C      5         hydrogen bond  IC8 ( I acts as acceptor)
C
C      6         SS bridges
C      7         CIS
C      8         link
C      9         gap
C     10         modification
C ----------------------------------
      integer maxhent,maxconnp,maxssbnd
      PARAMETER ( MAXHENT  =  50 )
      PARAMETER ( MAXCONNP = 400 )
      PARAMETER ( MAXSSBND = 2000 )
      COMMON /PDB_HENT/ NCONN_PDB,ICON1_PDB,ICON2_PDB,ICONC_PDB
     *                 ,NSS_PDB,NSS_1,NSS_2,NSS_C,NSS_DIST
     *                 ,NHENT,HENT_NA,HENT_ID,HENT_NAME,HENT_FORMUL
     *                 ,NSS_CODE1,NSS_CODE2,NSS_SYMM1,NSS_SYMM2
     *                 ,NSS_RES1,NSS_RES2
     *                 ,NSS_ID,ICONN_SYMM1,ICONN_SYMM2
      INTEGER*4  NCONN_PDB
      INTEGER*4  ICON1_PDB  (MAXCONNP)
      INTEGER*4  ICON2_PDB  (MAXCONNP)
      INTEGER*4  ICONC_PDB  (MAXCONNP)
      INTEGER*4  NSS_PDB
      INTEGER*4  NSS_1      (MAXSSBND)
      INTEGER*4  NSS_2      (MAXSSBND)
      INTEGER*4  NSS_C      (MAXSSBND)
      REAL       NSS_DIST   (MAXSSBND)
      INTEGER*4  NHENT
      INTEGER*4  HENT_NA    (MAXHENT)
      CHARACTER  HENT_ID    (MAXHENT)*3
      CHARACTER  HENT_NAME  (MAXHENT)*40
      CHARACTER  HENT_FORMUL(MAXHENT)*40
      CHARACTER  NSS_CODE1  (MAXSSBND)*15
      CHARACTER  NSS_CODE2  (MAXSSBND)*15
      CHARACTER  NSS_SYMM1  (MAXSSBND)*16
      CHARACTER  NSS_SYMM2  (MAXSSBND)*16
      CHARACTER  NSS_RES1   (MAXSSBND)*3
      CHARACTER  NSS_RES2   (MAXSSBND)*3
      CHARACTER  NSS_ID     (MAXSSBND)*16
      CHARACTER  ICONN_SYMM1(MAXCONNP)*6
      CHARACTER  ICONN_SYMM2(MAXCONNP)*6
C ------------------------------------