Table I.

ERAP1 alleles associated with an altered risk of Ankylosing Spondylitis

SNP#	P value association with AS	Allele	349	528	575	725	730
		ERAP1 High	M	K	D	R	Q
		ERAP1 Low	V	R	N	Q	E
rs2287987	1.6×10^−4	M349V	V	K	D	R	Q
rs30187	3.0×10^−6	K528R	M	R	D	R	Q
rs10050860	1.1×10^−4	D575N	M	K	N	R	Q
rs17482078	2.3×10^−4	R725Q	M	K	D	Q	Q
rs27044	1.0×10^−6	Q730E	M	K	D	R	E
		HeLa (endogenous)	M/M (atg/atg)	K/R (aag/agg)	D/D (gac/gac)	R/R (cga/cga)	Q/E (caa/gaa)

Construction of plasmids, encoding for various ERAP1 alleles was performed as described in Materials and Methods. P value for association with AS is derived from recent GWAS studies (1–4), predominantly study described in (3) on UK patients. Amino acids positions, associated with high risk of AS are shown in grey. Endogenous ERAP1 alleles in our HeLa-Kb-B27/47 resemble ERAP1_High, however, have heterogeneity at positions 528 and 730.