# OERotamer¶

struct OERotamer


This class represents an OERotamer, an abstraction of a frequently observed conformation of an amino-acid sidechain. Statistical surveys of sidechain conformations for well-curated sets of protein structures reveal that almost all can be assigned to a limited number of clusters. The mean, or more usefully the mode, of each cluster’s dihedral angles can be used to represent the cluster as a whole. Collections of these dihedral angles, along with the observed probability of the associated cluster is known as a rotamer library.

The following function returns an OERotamer iterator over each rotamer for a given amino-acid in a specific rotamer library:

The following function takes an OERotamer as an argument and modifies the 3-dimensional structure of a particular amino-acid sidechain so that the dihedral angles are that of the rotamer:

## GetChi1¶

float GetChi1() const


Return the value of the sidechain $$\chi_1$$ dihedral angle, N-CA-CB-xG(1).

## GetChi2¶

float GetChi2() const


Return the value of the sidechain $$\chi_2$$ dihedral angle, CA-CB-xG(1)-xD(1).

## GetChi3¶

float GetChi3() const


Return the value of the sidechain $$\chi_3$$ dihedral angle, CB-xG-xD-xE(1).

## GetChi4¶

float GetChi4() const


Return the value of the sidechain $$\chi_4$$ dihedral angle, xG-xD-xE-xZ.

## GetProbability¶

float GetProbability() const


Return the probability assigned to this rotamer by the rotamer library used to set the rotamer parameters (see OERotamerLibrary).

## GetResidueIndex¶

unsigned int GetResidueIndex() const


Return the OEResidueIndex value indicating the type of amino-acid residue used to set the rotamer parameters.