Package org.jmol.dssx

Class DSSP


  • public class DSSP
    extends Object
    • Field Detail

      • vHBonds

        private javajs.util.Lst<Bond> vHBonds
      • done

        private javajs.util.BS[] done
      • doReport

        private boolean doReport
      • dsspIgnoreHydrogens

        private boolean dsspIgnoreHydrogens
      • setStructure

        private boolean setStructure
      • labels

        private char[][] labels
      • bsBad

        private javajs.util.BS bsBad
      • bioPolymerCount

        private int bioPolymerCount
      • htLadders

        private Map<int[][],​Boolean> htLadders
      • bridgesA

        private javajs.util.Lst<Bridge> bridgesA
      • bridgesP

        private javajs.util.Lst<Bridge> bridgesP
      • isDSSP2

        private boolean isDSSP2
      • sheetOffsets

        private int[][] sheetOffsets
    • Constructor Detail

      • DSSP

        public DSSP()
    • Method Detail

      • calculateDssp

        public String calculateDssp​(Object[] objBioPolymers,
                                    int bioPolymerCount,
                                    Object objVHBonds,
                                    boolean doReport,
                                    boolean dsspIgnoreHydrogens,
                                    boolean setStructure,
                                    int version)
        Parameters:
        objBioPolymers -
        bioPolymerCount -
        objVHBonds -
        doReport -
        dsspIgnoreHydrogens -
        setStructure -
        version - can be 2.0 to reverse order of helix calculation and emphasize pi-helices
        Returns:
        helix-5, helix-4, helix-3, and SUMMARY lines
      • getDualHydrogenBondArray

        private int[][][][] getDualHydrogenBondArray()
        (p. 2579): Hydrogen bonds in proteins have little wave-function overlap and are well described by an electromodel: E = q1q2(1/r(ON) + 1/r(CH) - 1/r(OH) - 1/r(CN)) * f with q1 = 0.42e and q2 = 0.20e, e being the unit electron charge and r(AB) the interatomic distance from A to B. In chemical units, r is in angstroms, the dimensional factor f = 332, and E is in kcal/mol. We ... assign an H bond between C=O of residue i and N-H of residue j if E is less than the cutoff, i.e., "Hbond(i,j) =: [E < -0.5 kcal/mol]."
        Returns:
        array of dual-minmum NH→O=C H bonds
      • getBridges

        private void getBridges​(int[][][][] min)
        (p. 2581): Two nonoverlapping stretches of three residues each, i-1,i,i+1 and j-1,j,j+1, form either a parallel or antiparallel bridge, depending on which of two basic patterns (Fig. 2) is matched. We assign a bridge between residues i and j if there are two H bonds characteristic of beta-structure; in particular: Parallel Bridge(i,j) =: [Hbond(i-1,j) and Hbond(j,i+1)] or [Hbond(j-1,i) and Hbond(i,j+1)] Antiparallel Bridge(i,j) =: [Hbond(i,j) and Hbond(j,i)] or [Hbond(i-1,j+1) and Hbond(j-1,i+1)]
        Parameters:
        min -
      • getSheetStructures

        private void getSheetStructures()
        "sheet =: a set of one or more ladders connected by shared residues" (p. 2582)
      • createLadders

        private void createLadders​(javajs.util.Lst<Bridge> bridges,
                                   boolean isAntiparallel)
        "ladder =: one or more consecutive bridges of identical type" (p. 2582) "For beta structures, we define explicitly: a bulge-linked ladder consists of two (perfect) ladder or bridges of the same type connected by at most one extra residue on one strand and at most four extra resideus on the other strand.... all residues in bulge-linked ladders are marked "E," including the extra residues." (p. 2585)
        Parameters:
        bridges -
        isAntiparallel -
      • checkBridge

        private boolean checkBridge​(Bridge bridge,
                                    boolean isAntiparallel,
                                    int n1,
                                    int n2)
        check to see if another bridge exists offset by n1 and n2 from the two ends of a bridge
        Parameters:
        bridge -
        isAntiparallel -
        n1 -
        n2 -
        Returns:
        TRUE if bridge is part of a ladder
      • checkBulge

        private void checkBulge​(Bridge bridge,
                                boolean isAntiparallel,
                                int dir)
      • isHbonded

        private int[] isHbonded​(int indexDonor,
                                int indexAcceptor,
                                int pDonor,
                                int pAcceptor,
                                int[][][][] min)
      • findHelixes

        private String findHelixes​(int iPolymer,
                                   int[][][] min)
        (p. 2581): A basic turn pattern (Fig. 2) is a single H bond of type (i,i+n). We assign an n-turn at residue i if there is an H bond from CO(i) to NH(i+n).... When the pattern is found, the ends of the H bond are indicated using ">" at i and "<" at i+n...; the residues bracketed by the H bond are noted "3," "4," or "5" unless they are also end points of other H bonds. Coincidence of ">" and "<" at one residue is indicated by "X." ... Residues bracketed by the hydrogen bond are marked "T," unless they are part of an n-helix (defined below). (p. 2582): A minimal helix is defined by two consecutive n-turns.... Longer helices are defined as overlaps of minimal helices.... Residues bracketed by H bonds are labeled G, H, I.... Long helices can deviate from regularity in that not all possible H bonds are formed. This possibility is implicit in the above helix definition.
        Parameters:
        min -
        iPolymer -
        Returns:
        string label
      • findHelixes2

        private String findHelixes2​(int mmtfType,
                                    int iPolymer,
                                    int pitch,
                                    int[][][] min,
                                    STR subtype,
                                    int type,
                                    javajs.util.BS bsTurn,
                                    boolean isFirst)
      • setTag

        private void setTag​(char[] tags,
                            javajs.util.BS bs,
                            char ch)