Table 1. The distribution of protein sequences and structures over the three classes of thermostability.

Mesophilic sequences	13111756
Thermophilic sequences	661072
Psychrophilic sequences	382564
Mesophilic structures	23069
Thermophilic structures	7741
Psychrophilic structures	140
Pfams with at least one Mesophilic structure	2306
Pfams with at least one Thermophilic structure	957
Pfams with at least one Psychrophilic structure	82
Pfams with at least 20 Thermophilic sequence	3355
Pfams with at least 20 Psychrophilic sequence	3046