env.Ztest: Preferred/Avoided Amino Acids Within an Environment
Description
Searches for amino acids either overrepresented or avoided at given positions within a sequence environment.
Usage
env.Ztest(pos, ctr, alpha = 0.05)
Value
Returns a list with three elements: (1) a matrix with the values of the Z statistical. (2) A dataframe with information regarding amino acid overrepresented in the positive environments, and (3) a dataframe similar to the previous one, but for amino acids avoided from the positive environments.
Arguments
pos
a 21 x m matrix containing the absolute frequencies of 21 amino acids at the m positions, in the positive environments.
ctr
a 21 x m matrix containing the absolute frequencies of 21 amino acids at the m positions, in the control environments.
alpha
significance level.
Author
Juan Carlos Aledo
Details
Please, note that in addition to the 20 proteinogenetic amino acid we are using the symbol X when the target (central) residue is closer to the N-terminal or C-terminal of the protein than the radius used.
References
Aledo et al. Sci Rep. 2015; 5: 16955. (PMID: 26597773)