Table 2.

Relative Accessibility of ω⁺ Residues

	LUP 1CDQ			MUP 1MUP			OBP 1OBP			V2R 1EWK
Family structure (PDB)	All	ω⁺	All	ω⁺	All	ω⁺	All	ω⁺	All	ω⁺
Total number of residues	72	15	157	32	158	33	324	8	274	43
No. buried	14	1	40	7	41	3	140	2	74	11
No. intermediate	18	4	52	14	59	13	93	3	133	21
No. exposed	40	10	65	11	58	17	91	3	67	11
% buried	19.4	6.7	25.5	21.9	25.9	9.1	43.2	25.0	27.0	25.6
% intermediate	25.0	26.7	33.5	43.8	37.3	39.4	28.7	37.5	48.5	48.8
% exposed	55.6	66.7	41.4	34.4	36.7	51.5	28.1	37.5	24.5	25.6

Protein structure information obtained from PDB (www.rcsb.org/pdb/) was selected, and residues corresponding to bound ligands were removed. The accessibility of individual amino acids was determined using DSSP (Kabsch and Sander 1983) and default parameters. Relative accessibility scores were calculated as: relative accessibility = (DSSP score/maximal accessibility of amino acid type) × 100. Results were fractionated into three states: buried (<9% relative accessibility), intermediate (9%—35% relative accessibility) and exposed (≥36% relative accessibility) (Rost and Sander 1994). The relative accessibility scores for all residues and ω⁺ residues are shown.

Evolution and Comparative Genomics of Odorant- and Pheromone-Associated Genes in Rodents