3.2 Prediction of functional constraints of the TMPRSS2 across vertebrate species
We scored the TMPRSS2 protein sequence for all the collected 164 species (Table 1 & Table S3). Scores from high to low were correspondent to Mammalia, Aves, Reptilia, Amphibia, Osteichthyes and Chondrichthyes, except for the Puma concolor, Athene cunicularia, Geospiza fortisand Anarrhichthys ocellatus , because these four species have amino change at the catalytic triad of TMPRSS2. From the global point of view, this result was highly consistent with the prediction from the phylogenetic tree. As expected, the primates scored the highest marks of over 95. Besides, other animals have been proven to be infected with the SARS-CoV-2, including pangolin, cat, dog, and hamster, have scored higher than 91. Especially, no damaging amino acid change was predicted in the hamster. In addition, only one probably or possibly damaging mutation was found in rat and mouse, even lesser than that of pangolin and cat. When focusing on animals that are closely related to humans, livestock has a much higher score than that of poultry.
Table 1. Prediction of functional constraints of the TMPRSS2 in 36 selected species.