Table 7. Statistics with tertiary salt bridges.
This table summarizes the results of tertiary salt bridge counts. For every protein, we calculated the average number of salt bridges present in thermophiles and in mesophiles, shown in columns 3 and 4. Column 5 shows the difference between the two. Based on this difference we set up a scoring scheme that qualitatively describes the relative abundance of tertiary salt bridges. If the difference is > 1.0, a positive (+) sign is assigned showing a predominance of salt bridges in thermophiles; if the difference is < -1.0, a negative (-) sign is assigned showing a predominance of salt bridges in mesophiles; for any other value of difference, no sign is assigned to either thermophiles or mesophiles, thus showing no bias for salt bridges. Note that in the two main categories (ribosomal proteins and tRNA synthetases thermophiles) thermophiles have a higher amount of tertiary salt bridges than mesophiles.