Re: What is the average distance between proteins in a cell?

Although it varies depending on where one looks in a cell, for globular
proteins floating freely the surface-surface distance is estimated to be 5
nm or less.  This is equivalent to about <=14 layers of water molecules.  The
distance between proteins in large protein complexes is obviously much
smaller while the distance in membranes could be more or less depending on
the number of proteins in the membranes, a value that is usually in flux.

One good reference is: Pollack, G.H. "Cells, Gels, and the Engines of Life"
Ebner and Sons, 2001 (www.cellsandgels.com).