Number of contacts of the hot spots.

<p>A. The degree distributions of the BB and SC hot spots are plotted on a semi-log scale. The degree distribution <i>P(k)</i> of the SC hot spots decreases exponentially (R² = 0.99). B. Linear correlation between the number of atoms of a SC hot spot and its tendency to have more than one contact. The ratio of the frequency of an amino acid in multiple contacts to its frequency in single contact is plotted against the number of its side chain atoms. C. Probability of a SC hot spot to have <i>k</i> contacts. The probabilities for a SC hot spot to have <i>k</i>>3 (♦) or <i>k</i> = 1 (○) are plotted against the number of atoms of its respective amino acid. The horizontal line indicates the probability at which every amino acid has the same probability to have <i>k</i> contacts (0.05 = 1/20). The vertical line indicates a number of atoms equals to 14.</p

Observed SC Pair occurrences.

<p>The values in a given row are the occurrences of the residue <i>a</i> in contact with the residues <i>b_i</i>, cited on columns. Thus, there are twenty rows <i>a_i</i> and twenty column <i>b_i,</i> - <i>i</i>- covering the 20 different amino acids. Due to the counting procedure the table is read row-wise (material and methods).</p

Local preferences of the charged amino acids in the SC hot spots.

<p>Local preferences of the charged amino acids in the SC hot spots.</p

SC and BB hot spot geometrical pair tendencies.

<p>Legend as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0094745#pone-0094745-t009" target="_blank">table 9</a>. L, M and S stand for long, medium and short side chains. × stands for L, M and S.</p

Chemical properties of the intermolecular β-strands and of the whole chains (%).

<p>Chemical properties of the intermolecular β-strands and of the whole chains (%).</p

General features of the dataset.

<p>A. Histogram of the lengths (number of amino acids) of the whole chains (black bar) and of the intermolecular β-strands (white bar). B. Histogram of the number of hot spot pairs in the intermolecular β-strands (white bar) and in the whole interface (black bar). The inset is a box of the number of amino acid pairs in the intermolecular β-strands (quartile distribution). The values within the box (interquartile) represent 75% of the dataset. The points above the third quartile Q₃ (outside of the box) are β-interfaces whose number of amino acid pairs deviates significantly from the rest of the dataset.</p

Ratio of f_ab/(f_a.f_b) for the BB hot spot pairs.

<p>Ratio of f_ab/(f_a.f_b) for the BB hot spot pairs.</p

SC and BB hot spot pair chemical tendencies.

<p>The number of pairs with a ratio SC pair frequency to BB pair frequency above 1.0±0.2 indicates the SC pair tendency. The number of pairs with a ratio below 0.8±0.2 indicates the BB pair tendency (table based on <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0094745#pone-0094745-g002" target="_blank">Fig. 2C</a>). The second column, total, indicates the pair combinatory of the chemical pair property mentioned in the first column. Fhi, Ch and P stand for hydrophobic, charged and polar residues. X stands for fhi, ch and P.</p

Comparison of the 210 frequencies of the BB and SC hot spot pairs.

<p>The frequencies of the SC hot spots pairs are plotted against those of the BB hot spots pairs, both in log scale. Pairs with identical BB and SC frequencies are on the diagonal. Pairs more frequent in SC are found above the diagonal whereas pairs more frequent in BB are found below the diagonal.</p

Ratio of f_ab/(f_a.f_b) for the SC hot spot pairs.

<p>Ratio of f_ab/(f_a.f_b) for the SC hot spot pairs.</p