Solution studies indicate that an equimolar mixture of the three peptides forms a helical trimer with high specificity and stability.
The thicknesses of the-PSI trimer and CP43'-PSI trimer supercomplex are approximately the same, as seen in Fig.
This confirms that the porphyrin trimer has exactly the right size to bind the exo product.
Differences between the dimer and trimer profiles revealed sequence patterns that match and extend experimental studies of oligomer specification.
The Gln 16 side chain was accommodated by qualitatively different interactions in the dimer and trimer crystal structures.