Interface conservation between IML3/CHL4 complex and other CCAN proteins

Conservation in protein interfaces: importance and inference

The criteria to determine conserved residues is based on the result of alignment. Residues scoring over 7 are considered as conserved.

Fig.1 Contribution of conservation to interfaces

Frequency of conserved interfacing residues in each interface, indicating the importance of the conserved residues to the interface interactions. G and J are DNA strands.

How conservation at interfaces is crucial for function

Over half of the interfacing residues are conserved, illustrating the contribution of conservation to subunit-subunit interfaces.  

It is worth noting that in the interfaces of CHL4-DNA (Fig.1 N-G&N-J), residues are mostly conserved, which might be significant for the function of kinetochore - segregating microtubles and centromeric chromatin. 

Fig.2 Inference of conservation

Frequency of conserved interfacing residues to total conserved residues.

Can conservation predict an interface?

The ratio of conserved interfacing residues to total conservation (lower than 50%) indicates that the prediction of a conserved residue to be in the interface is unreliable.

However, the conserved residues account for about half of the total sequence (220/458) in CHL4, suggesting that conservation of residues is a crucial part in other features of proteins, such as structural components.