In PyMOL

Click on Wizard -> Measurement -> Measurement mode (Distances) -> Click on first atom* -> Click on second atom*.

*Select atoms accordingly

Regards

Anu Manhas

You can use the"boundingBox" script ( https://pymolwiki.org/index.php/Bounding_Box ) or "DrawBounding box" script ( https://pymolwiki.org/index.php/DrawBoundingBox ) to determine the dimension.

The "split_chains" script ( https://pymolwiki.org/index.php/Split_chains )will put the different chains into separate objects

Dear Basit Sharif ,

Click on Wizard -> Measurement -> Measurement mode (Distances) -> Click on first atom* -> Click on second atom*.

or you can select atoms as your wish.

Dear Anu Manhas & Shaban Ahmad thank you for your answers but this method is just to find the distance between two atoms in a molecule . I want to calculate the whole size of protein and its dimensions.

Dear Annemarie Honegger Thank you for your answer. Let me check this method. Than I will tell whether it worked or not. It looks quite complicated and firstly I need to understand it properly.

If you will select the two farthest atoms (from the opposite side of the protein chain), it will give you the distance, i.e., the size of the protein.

or You can follow the link: https://pymolwiki.org/index.php/Draw_Protein_Dimensions

This script will draw the dimensions of a protein-based on an Inertia Axis Aligned Bounding Box (IABB).

Regards

Anu Manhas

Anu Manhas ok Thank you so much. Let me check this.