TABLE 2.

Comparison of cleavage sites recognized by coronavirus PLP1 and PLP2 activitiesd

Cleavage productsAmino acid at cleavage site position:Reference(s)
P6P5P4P3P2P1P1′P2′
Cleaved by PLP1
    MHV p28/p65LK/RaGYRaGaVK12, 20
    MHV p65/p210WRaFPCAaGaK7
    HCoV p9/p87GKaRGGGaNV17
Cleaved by PLP1 and PLP2
    HCoV p87/p210bFTKAAGGK43
Cleaved by PLP2
    IBV p87/p195cVVCKAGaGK25
    IBV p195/p41cVEKKAaGaGI26
    MHV p210/p44FaSLKGaGaAVThis paper
  • a A critical determinant for PLP processing as determined by mutagenesis studies.

  • b In vitro transcription-translation studies indicate that both PLP1 and PLP2 can cleave at this site. Critical determinants have not been identified.

  • c A revised alignment study indicates that the domain previously referred to as IBV PLPD has an inactive PLP1 domain and an active PLP2 domain (43).

  • d The arrow indicates where the polyprotein is cleaved.