Fig 1. The conserved domain regions and the catalytic triad of TMPRSS2 in selected animals. A. The protein secondary structure of TMPRSS2 predicted by SWISS-MODEL[19] and the catalytic triad amines. B. The TMPRSS2 has three conserved domain regions: LDLa, SRCR_2 and Tryp_SPc. Three catalytic triad H296, S435 and D441 were ultra-conserved across species.