Overall Structural Difficulty (SD) Index

Secondary Structural Features

% Number of Residues in Helices
% Number of Residues in Strands
% Number of Residues in Coils
Helices Count per 100 Residues
Strands Count per 100 Residues
Coils Count per 100 Residues
Structural Difficulty By Secondary Structural Features

Homology Based Features

PDB Identifier of Template Structure
Chain Length of Template Structure
% Coverage of Query and Template Alignment
% Identity of Query and Template Alignment
% Positives of Query and Template Alignment
Ratio of Aligned Residues to Template Length
Absolute Deviation from Amino Acid Occurrence Frequencies
Structural Difficulty By Homology Based Features

Physico-Chemical Features

Amino Acid Composition

Amino Acid	Count	%Frequency		Amino Acid	Count	%Frequency
Alanine (A)				Leucine (L)
Arginine (R)				Lysine (K)
Asparagine (N)				Methionine (M)
Aspartic Acid (D)				Phenylalanine (F)
Cysteine (C)				Proline (P)
Glutamine (Q)				Serine (S)
Glutamic Acid (E)				Threonine (T)
Glycine (G)				Tryptophan (W)
Histidine (H)				Tyrosine (Y)
Isoleucine (I)				Valine (V)

Ratio Aromatic Residues - Aliphatic Residues Aromatic Residues + Aliphatic Residues
Ratio Non-polar Residues - Polar Residues Non-polar Residues + Polar Residues
% Number of Charged Residues
Aliphatic Index
Instability Index
Structural Difficulty By Physico-Chemical Features