Complex sentence: The receptors m1 and m2 were determined based upon partial sequencing of M 1 and M 2 receptor proteins, the others were found by searching for homology, using bioinformatic techniques.
Split into simpler sentences: The receptors m1 and m2 were determined based upon partial sequencing of M 1 and M 2 receptor proteins. The others were found by searching for homology, using bioinformatic techniques.