sentences:  CR3 and CR4 have been shown to be 87% homologous via sequence analysis of human cDNA of the α chains; however, the complement receptors bind at distinct sites of iC3b and the intracellular domains differ in length and amino acid sequence, suggesting further differences in their functions.Further, CR3 favors binding to positively charged species, while CR4 binds negatively charged species.It has been shown that both CR3 and CR4 are found in mince and humans.