Comparison of JAK2 and JAK3 structures. (A) Molecular surface representation of JAK2 PTK domain in complex with CMP6. (B) Molecular surface representation of JAK3 PTK domain in complex with AFN941. The Graphical Representation and Analysis of Surface Properties program (GRASP)⁵²  was used to color code surfaces by electrostatic potential. (C) Superposition of JAK2 kinase domain bound to CMP6 and JAK3 kinase domain bound to AFN941. JAK2 is colored in violet, and JAK3 is colored in green. (D) Close-up of the catalytic cleft of JAK2 and JAK3 kinase domain. CMP6 is colored in yellow and AFN941 in pink.