# `class pdb.BackboneHB`

Available on all platforms

Container for hydrogen bond energy between two residues. This only consider hydrogen bonds between backbone N-H and C=O.

## Instance Fields

### `var E01:WMHydrogenBond`

hydrogen bond energy for res0(N) - res1(O)

### `var E10:WMHydrogenBond`

hydrogen bond energy for res1(N) - res0(O)

### `function new(r0:PdbResidue, r1:PdbResidue):Void`

Constructor. If two residues are given, backbone hydrogen bond energy is calculated. See also `calc` function.

### `function bonded(threshold:Float):Bool`

return whether there is a hydrogen bond or not

### `function calc(r0:PdbResidue, r1:PdbResidue):Void`

calculate backbone hydrogen bond between two residues. Note that this function does not return hydrogen bond energy. Use `getEne` function if you need hydrogen bond energy or `bonded` function if you want to know whether hydrogen bond exists between residues.

### `function getEne():Float`

return hydrogen bond energy in this definition