What are the components of Crispr/Cas9?

Cas9: a nuclease that is originally isolated from S. pyrogenes, an effector protein. sgRNA: single guide RNA that arises because of the fusion of the gene specific crRNA sequence to the scaffold tracrRNA sequence. PAM: protospacer adjacent motif, a 2-6 basepair DNA sequence that immediately follows the DNA sequence that is targeted by Cas9.