Table 1. Hydrogen-bond analysis of the PDB as a function of nominal crystallographic resolution.

Resolution	Total H-Bonds	α-Helix Bonds	310-Helix Bonds	β-Sheet Bonds	Shared 3-center H-bonds
0.00–0.49	101188	34594	14873	20531	14283
0.50–0.99	33446	9693	2345	12329	1980
1.00–1.49	718464	246901	57088	230275	47186
1.50–1.99	5342073	1942587	451007	1595126	375252
2.00–2.49	7739951	2936903	719304	2157150	626744
2.50–2.99	5178485	1922736	537574	1458120	505260
3.00–3.49	1839170	672369	202288	493697	210678
3.50–3.99	406006	141464	44390	109627	51326
4.00–4.49	137350	51589	15757	32724	18208
4.50–4.99	32332	12830	4077	6711	4205