Why are some protein complexes composed of many different types of proteins? How many different types are they composed of? In particular, which protein complex has the greater number of different types of proteins in it?
For example, I've read that the ribosome consists of 70-80 different types of proteins.
How many different types of proteins are in the spliceosome for example?
I'm using the phrasing "types of proteins" to distinguish aggregates/complexes composed of many different copies of the same protein (i.e. some viral capsids) from those composed of many different kinds (i.e. ribosome, exosome complex, spliceosome).