Table 2. Analysis of the tetrameric interfaces of the two BenM EBD structures and the structure of CbnR from Ralstonia eutropha .

	Structure A (PDB code 2f97)	Structure B (PDB code 2f8d)	CbnR† (PDB code 1iz1)
Interface-accessible surface area (2)	882.84	997.6	854.57
Interface-accessible surface area (%)	8.01	8.79	8.17
Planarity‡	2.78	3.12	2.62
Length/breadth ()	40.59/18.61	40.01/22.63	37.74/24.02
Length/breadth ratio	0.33	0.28	0.56
Secondary-structure classification§
Polar atoms in interface (%)	48.8	43.0	42.8
Nonpolar atoms in interface (%)	52.2	57.0	57.2
Segmentation¶	6 (4)	5 (4)	4 (3)

^†Computations were performed using the A and P monomers of CbnR which constitute its tetrameric interface. CbnR has one tetramer per asymmetric unit. The DNA-binding domain and helix linker (residues 189) of CbnR were excluded from calculations.

^‡Planarity is a measure of how far the interface residues deviate from a best-fit plane. This plane is calculated through the three-dimensional coordinates of the atoms in the interface using principal-component analyses.

^§Secondary-structure classification represents the secondary-structure feature that occurs with the greatest frequency of and secondary structures in the interface residues.

^¶Segmentation is the number of discontinuous segments of the polypeptide involved in the interface interaction. The number in parentheses refers to the number of segments that result when segments containing single or double residues are not considered as separate segments.