Table 2.

Selected properties for the clusters of pathogen-associated proteins

Cluster	C1	C7	C8	C6	C3	C9	C5	C10	C11	C2	C4	C12
# Proteins	268	150	110	166	411	149	180	279	236	409	210	262
Characteristic	Secretion signal			Molecular weight	Hydrophobic		Negative charge		Positive charge		Proline	Aromatic
Secretion	↑	↑	↑
Molecular weight			↑	↑
Protein charge			↓		↓	↓	↓	↓	↑	↑		↑
Tiny		↑	↑		↓		↓	↓		↑	↑	↓
Small		↑	↑		↓	↑		↓			↑	↓
Aliphatic	↑				↑	↑		↓	↓		↓
Aromatic	↑		↓			↓	↓	↑	↓			↑
Polar	↓	↓			↓		↑		↑		↑
Charged	↓	↓	↓				↑	↑	↑
Basic	↓	↓	↓			↓			↑	↑
Acidic	↓						↑			↓
Serine (S)					↓					↑
Threonine (T)			↑
Leucine (L)	↑		↓		↑				↓
Cysteine (C)		↑					↓
Glycine (G)		↑
Proline (P)											↑

For each feature in the 35-dimensional feature vector, Mann–Whitney U tests were used to test whether the distribution within a cluster is identical to the full background distribution for all clusters and highly significant p-values for both directions (lesser ↓ and greater ↑, p-value < 2.2e-16) are shown. Secretion refers to the predicted SignalP score and WoLF PSORT extracellular score. The following amino acid membership are used: tiny (A,C,G,S,T), small (A,C,D,G,N,P,S,T,V), aliphatic (A,I,L,V), aromatic (F,H,W,Y), polar (D,E,H,K,N,Q,R,S,T), charged (D,E,H,K,R), basic (H, K, R) and acidic (D, E).