BackboneMorph

Move matched backbone residues in order and fade unmatched residues.

View source Guide and examplesInherits Animation

from proteinmotion import BackboneMorph

Constructor

BackboneMorph(
    source,
    destination,
    *,
    match=None,
    residue_delay=0.008,
    fade_out=(0.0, 0.35),
    fade_in=(0.65, 1.0),
    align=True,
    motion_easing='smooth',
    **match_options,
)

Parameters

Parameter	Default	Description
`source`	Required	Source Protein.
`destination`	Required	Destination Protein.
`match`keyword only	`None`	ContactMatch correspondence; None computes one using match_options.
`residue_delay`keyword only	`0.008`	Delay in seconds between successive residue starts.
`fade_out`keyword only	`(0.0, 0.35)`	Normalized progress interval for fading unmatched source residues.
`fade_in`keyword only	`(0.65, 1.0)`	Normalized progress interval for fading unmatched destination residues.
`align`keyword only	`True`	Align the destination to the source before interpolation.
`motion_easing`keyword only	`'smooth'`	Per-residue motion: "smooth" or "linear".
`**match_options`	—	Options passed to match_backbones() when match is None.

Notes

Each matched residue moves for run_time − (matched count − 1) × residue_delay seconds. Unmatched source and destination residues use fade_out and fade_in intervals. Both proteins’ geometry, transforms, and opacity belong to this animation. In ball-and-stick mode, atoms translate with their residue Cα and the atom sets crossfade. Side-chain atoms use their original residue geometry.

Example and output

Run this command from a repository checkout.

Code Render command

proteinmotion render examples/backbone_morph.py BackboneDemo \
  -o morph.mp4 --fps 60

Output Preview · 11.5 s · 30 fps

Calmodulin to troponin C morph

A contact-map match selects 114 Cα pairs. Matched residues move in sequence from N to C; unmatched residues fade out or in.

Full source: BackboneDemo Download MP4

Methods and properties

Name	Description
targetsproperty	Objects whose state this animation changes.
bind()method	Capture starting values when the scene schedules the animation.
apply()method	Evaluate the animation at eased progress alpha. Called by the timeline.