Instructions
Using the Results page from MakeMultimer (generated with the above button):

1. View the biological unit by clicking the link View in FirstGlance.
2. Interpret your results following the example below.

Example Explaining Interpretation
We'll use 1hho as our example. The asymmetric unit (published PDB file) of 1hho has 2 chains. In the Results, the biological unit(s) are called biomolecules.

- What is BIOMOLECULE 1? As you can see below, for 1hho, it is a TETRAMER (4 chains).
  - Sometimes there will be more than 1 biomolecule. Scroll down in the Results page to see.
- Who thinks it is a tetramer? As you can see below, the AUTHORS believe it is a tetramer.
  - When the "author determined" biomolecule has a different number of chains than the asymmetric unit, the biomolecule is likely to be correct.
  - When the "author determined" biomolecule has the same number of chains as the asymmetric unit, the biomolecule is less likely to be correct. (Authors sometimes forget to specify the known biomolecule in the PDB file. See examples and more about this problem.)
  - When a biomolecule is determined only by SOFTWARE, it is less likely to be correct.

- How was the biomolecule CONSTRUCTED?
  - The original chain A was duplicated to make 2 chains named A and C.
  - The original chain B was duplicated to make 2 chains named B and D.

For 1hho, the biological unit has more chains than the asymmetric unit. In other cases, the biological unit may have the same number of chains, or fewer chains. When the number is the same, the conformation is sometimes different! In Proteopedia, you will find a range of examples.
To try one of those examples, click on the PDB code. At the Proteopedia page on that PDB code, underneath the molecule, click on FirstGlance in the Resources line. In FirstGlance, click on Biological Unit.

Credits
This page is part of FirstGlance in Jmol (FirstGlance Credits). The MakeMultimer Server that generates the biological unit is the work of Michael Palmer.