Table 7. The ratios of intermolecular hydrogen bond and van der Waals contacts made between the protein and the base/backbone component of the nucleic acid for the three datasets of protein–nucleic acid complexes: protein–RNA (complete dataset), protein–dsDNA and protein–ssDNA.

Contact (base/backbone ratio)	RNA (all)	dsDNA	ssDNA	RNA
				Virala	Synthesisb	Modificationsc
Hydrogen bonds	1.0	0.5	0.9	1.2	0.6	2.4
van der Waals contacts	1.4	0.3	1.4	1.9	0.9	3.2

Ratios are also shown for the three functional subsets of the protein–RNA complexes: viral proteins^a, protein synthesis proteins^b and RNA modification proteins^c.