# `class pdb.HBParams`

Available on all platforms

Container for static variables for backbone hydrogen bond. Some of them come from STRIDE

## Class Fields

### `static var HB_dist:Float`

hydrogen bond length (between N and O) in angstrom

### `static var HB_ene:Float`

hydrogen bond reference energy in kcal/mol

### `static var NH_dist:Float`

distance between N and H; used when generating position of H

### `static var threshold_h3:Float`

threshold of 3-10 helix; smaller values mean strict threshold

### `static var threshold_hA:Float`

threshold of alpha-helix; smaller values mean strict threshold

### `static var threshold_hP:Float`

threshold of pi helix; smaller values mean strict threshold

### `static var threshold_s:Float`

threshold of beta strand; smaller values mean strict threshold