<!-- ============================================
     ::DATATOOL:: Generated from "mmdb1.asn"
     ::DATATOOL:: by application DATATOOL version 1.8.1
     ::DATATOOL:: on 01/18/2007 23:07:18
     ============================================ -->

<!-- ============================================ -->
<!-- This section is mapped from module "MMDB-Chemical-graph"
================================================= -->

<!--
**********************************************************************

  Biological Macromolecule 3-D Structure Data Types for MMDB,
                A Molecular Modeling Database

  Definitions for a chemical graph

  By Hitomi Ohkawa, Jim Ostell, Chris Hogue and Steve Bryant 

  National Center for Biotechnology Information
  National Institutes of Health
  Bethesda, MD 20894 USA

  July, 1995

**********************************************************************
-->

<!-- Elements used by other modules:
          Biostruc-graph,
          Biomol-descr,
          Residue-graph,
          Molecule-id,
          PCSubstance-id,
          Residue-id,
          Atom-id -->

<!-- Elements referenced from other modules:
          Pub FROM NCBI-Pub,
          BioSource FROM NCBI-BioSource,
          Seq-id FROM NCBI-Seqloc,
          Biostruc-id FROM MMDB -->
<!-- ============================================ -->

<!--
 A biostruc graph contains the complete chemical graph of the biomolecular 
 assembly.  The assembly graph is defined hierarchically, in terms of 
 subgraphs graphs of component molecules.  For PDB-derived biostrucs,
 the molecules forming the assembly are the individual biopolymer chains and 
 any non-polymer or "heterogen" groups which are present. 
 The PDB-derived  "compound name" field appears as the name within the
 biostruc-graph description.  PDB "class" and "source" fields appear as 
 explicit attributes.  PDB-derived structures are assigned an assembly type 
 of "other" unless they have been further classified as the "physiological
 form" or "crystallographic cell" contents.  If they have, the source of the 
 type classification appears as a citation within the  assembly description. 
 Note that the biostruc-graph also includes as literals the subgraphs of 
 any nonstandard residues present within it. For PDB-derived biostrucs these 
 subgraphs are constructed automatically, with validation as described below.
-->
<!ELEMENT Biostruc-graph (
        Biostruc-graph_descr?, 
        Biostruc-graph_molecule-graphs, 
        Biostruc-graph_inter-molecule-bonds?, 
        Biostruc-graph_residue-graphs?)>

<!ELEMENT Biostruc-graph_descr (Biomol-descr*)>

<!ELEMENT Biostruc-graph_molecule-graphs (Molecule-graph*)>

<!ELEMENT Biostruc-graph_inter-molecule-bonds (Inter-residue-bond*)>

<!ELEMENT Biostruc-graph_residue-graphs (Residue-graph*)>

<!--
 A biomolecule description refers to the chemical structure of a molecule or 
 component substructures.  This descriptor type is used at the level of
 assemblies, molecules and residues, and also for residue-graph dictionaries.
 The BioSource object type is drawn from NCBI taxonomy data specifications,
 and is not repeated here.
-->
<!ELEMENT Biomol-descr (
        Biomol-descr_name | 
        Biomol-descr_pdb-class | 
        Biomol-descr_pdb-source | 
        Biomol-descr_pdb-comment | 
        Biomol-descr_other-comment | 
        Biomol-descr_organism | 
        Biomol-descr_attribution | 
        Biomol-descr_assembly-type | 
        Biomol-descr_molecule-type)>

<!ELEMENT Biomol-descr_name (#PCDATA)>

<!ELEMENT Biomol-descr_pdb-class (#PCDATA)>

<!ELEMENT Biomol-descr_pdb-source (#PCDATA)>

<!ELEMENT Biomol-descr_pdb-comment (#PCDATA)>

<!ELEMENT Biomol-descr_other-comment (#PCDATA)>

<!ELEMENT Biomol-descr_organism (BioSource)>

<!ELEMENT Biomol-descr_attribution (Pub)>

<!ELEMENT Biomol-descr_assembly-type (%INTEGER;)>
<!ATTLIST Biomol-descr_assembly-type value (
        physiological-form |
        crystallographic-cell |
        other
        ) #IMPLIED >


<!ELEMENT Biomol-descr_molecule-type (%INTEGER;)>
<!ATTLIST Biomol-descr_molecule-type value (
        dna |
        rna |
        protein |
        other-biopolymer |
        solvent |
        other-nonpolymer |
        other
        ) #IMPLIED >


<!--
 A molecule chemical graph is defined by a sequence of residues.  Nonpolymers
 are described in the same way, but may contain only a single residue.  
 Biopolymer molecules are identified within PDB entries according to their
 appearance on SEQRES records, which formally define a biopolymer as such. 
 Biopolymers are defined by the distinction between ATOM and HETATM 
 coordinate records only in cases where the chemical sequence from SEQRES
 is in conflict with coordinate data. The PDB-assigned chain code appears as 
 the name within the molecule descriptions of the biopolymers.
 Nonpolymer molecules from PDB correspond to individual HETEROGEN groups, 
 excluding any HETEROGEN groups which represent modified biopolymer residues.
 These molecules are named according to the chain, residue type and residue 
 number fields as assigned by PDB. Any description appearing in the PDB HET 
 record appears as a pdb-comment within the molecule description. 
 Molecule types for PDB-derived molecule graphs are assigned by matching 
 residue and atom names against the PDB-documented standard types for protein,
 DNA and RNA, and against residue codes commonly used to indicate solvent.
 Classification is by "majority rule". If more than half of the residues in
 a biopolymer are standard groups of one type, then the molecule is of that 
 type, and otherwise classified as "other". Note that this classification does
 not preclude the presence of modified residues, but insists they constitute 
 less than half the biopolymer. Non-polymers are classified only as "solvent"
 or "other".  
 Note that a molecule graph may also contain a set of cross references 
 to biopolymer sequence databases.  All biopolymer molecules in MMDB contain 
 appropriate identifiers for the corresponding entry in the NCBI-Sequences 
 database, in particular the NCBI "gi" number, which may be used for sequence
 retrieval. The Seq-id object type is defined in the NCBI molecular sequence 
 specification, and not repeated here.
-->
<!ELEMENT Molecule-graph (
        Molecule-graph_id, 
        Molecule-graph_descr?, 
        Molecule-graph_seq-id?, 
        Molecule-graph_residue-sequence, 
        Molecule-graph_inter-residue-bonds?, 
        Molecule-graph_sid?)>

<!ELEMENT Molecule-graph_id (Molecule-id)>

<!ELEMENT Molecule-graph_descr (Biomol-descr*)>

<!ELEMENT Molecule-graph_seq-id (Seq-id)>

<!ELEMENT Molecule-graph_residue-sequence (Residue*)>

<!ELEMENT Molecule-graph_inter-residue-bonds (Inter-residue-bond*)>
<!-- Pubchem substance id -->
<!ELEMENT Molecule-graph_sid (PCSubstance-id)>


<!ELEMENT Molecule-id (%INTEGER;)>

<!-- Pubchem substance id -->
<!ELEMENT PCSubstance-id (%INTEGER;)>

<!--
 Residues may be assigned a text-string name as well as an id number. PDB 
 assigned residue numbers appear as the residue name.
-->
<!ELEMENT Residue (
        Residue_id, 
        Residue_name?, 
        Residue_residue-graph)>

<!ELEMENT Residue_id (Residue-id)>

<!ELEMENT Residue_name (#PCDATA)>
<!--
 Residue graphs from different sources may be referenced within a molecule
 graph.  The allowed choices are the nonstandard residue graphs included in 
 the present biostruc, residue graphs within other biostrucs, or residue 
 graphs within tables of standard residue definitions.
-->
<!ELEMENT Residue_residue-graph (Residue-graph-pntr)>


<!ELEMENT Residue-id (%INTEGER;)>

<!--
 Residue graphs from different sources may be referenced within a molecule
 graph.  The allowed choices are the nonstandard residue graphs included in 
 the present biostruc, residue graphs within other biostrucs, or residue 
 graphs within tables of standard residue definitions.
-->
<!ELEMENT Residue-graph-pntr (
        Residue-graph-pntr_local | 
        Residue-graph-pntr_biostruc | 
        Residue-graph-pntr_standard)>

<!ELEMENT Residue-graph-pntr_local (Residue-graph-id)>

<!ELEMENT Residue-graph-pntr_biostruc (Biostruc-graph-pntr)>

<!ELEMENT Residue-graph-pntr_standard (Biostruc-residue-graph-set-pntr)>


<!ELEMENT Biostruc-graph-pntr (
        Biostruc-graph-pntr_biostruc-id, 
        Biostruc-graph-pntr_residue-graph-id)>

<!ELEMENT Biostruc-graph-pntr_biostruc-id (Biostruc-id)>

<!ELEMENT Biostruc-graph-pntr_residue-graph-id (Residue-graph-id)>


<!ELEMENT Biostruc-residue-graph-set-pntr (
        Biostruc-residue-graph-set-pntr_biostruc-residue-graph-set-id, 
        Biostruc-residue-graph-set-pntr_residue-graph-id)>

<!ELEMENT Biostruc-residue-graph-set-pntr_biostruc-residue-graph-set-id (Biostruc-id)>

<!ELEMENT Biostruc-residue-graph-set-pntr_residue-graph-id (Residue-graph-id)>

<!--
 Residue graphs define atomic formulae, connectivity, chirality, and names.
 For standard residue graphs from the MMDB dictionary the PDB-assigned 
 residue-type code appears as the name within the residue graph description,
 and the full trivial name of the residue as a comment within that 
 description.  For any nonstandard residue graphs provided with an MMDB 
 biostruc the PDB-assigned residue-type code similarly appears as the name 
 within the description, and any information provided on PDB HET records as 
 a pdb-comment within that description.  
 Note that nonstandard residue graphs for a PDB-derived biostruc may be 
 incomplete. Current PDB format cannot represent connectivity for groups 
 which are disordered, and for which no coordinates are given.  In these 
 cases the residue graph defined in MMDB represents only the subgraph that 
 could be identified from available ATOM, HETATM and CONECT records.
-->
<!ELEMENT Residue-graph (
        Residue-graph_id, 
        Residue-graph_descr?, 
        Residue-graph_residue-type?, 
        Residue-graph_iupac-code?, 
        Residue-graph_atoms, 
        Residue-graph_bonds, 
        Residue-graph_chiral-centers?)>

<!ELEMENT Residue-graph_id (Residue-graph-id)>

<!ELEMENT Residue-graph_descr (Biomol-descr*)>

<!ELEMENT Residue-graph_residue-type (%INTEGER;)>
<!ATTLIST Residue-graph_residue-type value (
        deoxyribonucleotide |
        ribonucleotide |
        amino-acid |
        other
        ) #IMPLIED >


<!ELEMENT Residue-graph_iupac-code (Residue-graph_iupac-code_E*)>


<!ELEMENT Residue-graph_iupac-code_E (#PCDATA)>

<!ELEMENT Residue-graph_atoms (Atom*)>

<!ELEMENT Residue-graph_bonds (Intra-residue-bond*)>

<!ELEMENT Residue-graph_chiral-centers (Chiral-center*)>


<!ELEMENT Residue-graph-id (%INTEGER;)>

<!--
 Atoms in residue graphs are defined by elemental symbols and names.  PDB-
 assigned atom names appear here in the name field, except in cases of known 
 PDB synonyms.  In these cases atom names are mapped to the names used in the
 MMDB standard dictionary. This occurs primarily for hydrogen atoms, where 
 PDB practice allows synonyms for several atom types.  For PDB atoms the 
 elemental symbol is obtained by parsing the PDB atom name field, allowing 
 for known special-semantics cases where the atom name does not follow the
 documented encoding rule.  Ionizable protons are identified within standard 
 residue graphs in the MMDB dictionary, but not within automatically-defined
 nonstandard graphs.
-->
<!ELEMENT Atom (
        Atom_id, 
        Atom_name?, 
        Atom_iupac-code?, 
        Atom_element, 
        Atom_ionizable-proton?)>

<!ELEMENT Atom_id (Atom-id)>

<!ELEMENT Atom_name (#PCDATA)>

<!ELEMENT Atom_iupac-code (Atom_iupac-code_E*)>


<!ELEMENT Atom_iupac-code_E (#PCDATA)>

<!ELEMENT Atom_element %ENUM;>
<!ATTLIST Atom_element value (
        h |
        he |
        li |
        be |
        b |
        c |
        n |
        o |
        f |
        ne |
        na |
        mg |
        al |
        si |
        p |
        s |
        cl |
        ar |
        k |
        ca |
        sc |
        ti |
        v |
        cr |
        mn |
        fe |
        co |
        ni |
        cu |
        zn |
        ga |
        ge |
        as |
        se |
        br |
        kr |
        rb |
        sr |
        y |
        zr |
        nb |
        mo |
        tc |
        ru |
        rh |
        pd |
        ag |
        cd |
        in |
        sn |
        sb |
        te |
        i |
        xe |
        cs |
        ba |
        la |
        ce |
        pr |
        nd |
        pm |
        sm |
        eu |
        gd |
        tb |
        dy |
        ho |
        er |
        tm |
        yb |
        lu |
        hf |
        ta |
        w |
        re |
        os |
        ir |
        pt |
        au |
        hg |
        tl |
        pb |
        bi |
        po |
        at |
        rn |
        fr |
        ra |
        ac |
        th |
        pa |
        u |
        np |
        pu |
        am |
        cm |
        bk |
        cf |
        es |
        fm |
        md |
        no |
        lr |
        other |
        unknown
        ) #REQUIRED >


<!ELEMENT Atom_ionizable-proton %ENUM;>
<!ATTLIST Atom_ionizable-proton value (
        true |
        false |
        unknown
        ) #REQUIRED >



<!ELEMENT Atom-id (%INTEGER;)>

<!--
 Intra-residue-bond specifies connectivity between atoms in Residue-graph.
 Unlike Inter-residue-bond defined later, its participating atoms are part of
 a residue subgraph dictionary, not part of a specific biostruc-graph.
 For residue graphs in the standard MMDB dictionary bonds are defined from
 the known chemical structures of amino acids and nucleotides.  For 
 nonstandard residue graphs bonds are defined from PDB CONECT records, with
 validation for consistency with coordinate data, and from stereochemical
 calculation to identify unreported bonds.  Validation and bond identification
 are based on comparison of inter-atomic distances to the sum of covalent
 radii for the corresponding elements. 
-->
<!ELEMENT Intra-residue-bond (
        Intra-residue-bond_atom-id-1, 
        Intra-residue-bond_atom-id-2, 
        Intra-residue-bond_bond-order?)>

<!ELEMENT Intra-residue-bond_atom-id-1 (Atom-id)>

<!ELEMENT Intra-residue-bond_atom-id-2 (Atom-id)>

<!ELEMENT Intra-residue-bond_bond-order (%INTEGER;)>
<!ATTLIST Intra-residue-bond_bond-order value (
        single |
        partial-double |
        aromatic |
        double |
        triple |
        other |
        unknown
        ) #IMPLIED >


<!--
 Chiral centers are atoms with tetrahedral geometry.  Chirality is defined
 by a chiral volume involving the chiral center and 3 other atoms bonded to 
 it.  For any coordinates assigned to atoms c, n1, n2, and n3, the vector 
 triple product (n1-c) dot ( (n2-c) cross (n3-c) ) must have the indicated
 sign.  The calculation assumes an orthogonal right-handed coordinate system
 as is used for MMDB model structures.  
 Chirality is defined for standard residues in the MMDB dictionary, but is 
 not assigned automatically for PDB-derived nonstandard residues. If assigned
 for nonstandard residues, the source of chirality information is described 
 by a citation within the residue description.
-->
<!ELEMENT Chiral-center (
        Chiral-center_c, 
        Chiral-center_n1, 
        Chiral-center_n2, 
        Chiral-center_n3, 
        Chiral-center_sign)>

<!ELEMENT Chiral-center_c (Atom-id)>

<!ELEMENT Chiral-center_n1 (Atom-id)>

<!ELEMENT Chiral-center_n2 (Atom-id)>

<!ELEMENT Chiral-center_n3 (Atom-id)>

<!ELEMENT Chiral-center_sign %ENUM;>
<!ATTLIST Chiral-center_sign value (
        positive |
        negative
        ) #REQUIRED >


<!--
 Inter-residue bonds are defined by a reference to two atoms. For PDB-derived 
 structures bonds are identified from biopolymer connectivity according to
 SEQRES and from other connectivity information on SSBOND and CONECT 
 records. These data are validated and unreported bonds identified by
 stereochemical calculation, using the same criteria as for intra-residue 
 bonds.
-->
<!ELEMENT Inter-residue-bond (
        Inter-residue-bond_atom-id-1, 
        Inter-residue-bond_atom-id-2, 
        Inter-residue-bond_bond-order?)>
<!--
 Atoms, residues and molecules within the current biostruc are referenced 
 by hierarchical pointers.
-->
<!ELEMENT Inter-residue-bond_atom-id-1 (Atom-pntr)>
<!--
 Atoms, residues and molecules within the current biostruc are referenced 
 by hierarchical pointers.
-->
<!ELEMENT Inter-residue-bond_atom-id-2 (Atom-pntr)>

<!ELEMENT Inter-residue-bond_bond-order (%INTEGER;)>
<!ATTLIST Inter-residue-bond_bond-order value (
        single |
        partial-double |
        aromatic |
        double |
        triple |
        other |
        unknown
        ) #IMPLIED >


<!--
 Atoms, residues and molecules within the current biostruc are referenced 
 by hierarchical pointers.
-->
<!ELEMENT Atom-pntr (
        Atom-pntr_molecule-id, 
        Atom-pntr_residue-id, 
        Atom-pntr_atom-id)>

<!ELEMENT Atom-pntr_molecule-id (Molecule-id)>

<!ELEMENT Atom-pntr_residue-id (Residue-id)>

<!ELEMENT Atom-pntr_atom-id (Atom-id)>


<!ELEMENT Atom-pntr-set (Atom-pntr*)>