TABLE 1.

Structure-based comparison of sulfatase active site residues

Structural alignment of the modeled 6-O-sulfatase with the other sulfatases was obtained using the SuperPose tool (25). Residues that are highly conserved are displayed in boldface and non-conserved residues are listed in normal font. Regions of deletion are marked with the minus sign. Amino acids of 6-O-sulfatase that could potentially be involved in substrate binding are denoted with the asterisk.

6-O-Sulfatase (F. heparinum)	2-O-Sulfatase (F. heparinum)	Arylsulfatase A (human)	Arylsulfatase B (human)	Arylsulfatase (P. aeruginosa)
Cys-80	Cys-82	Cys-69	Cys-91	Cys-51
Arg-84	Arg-86	Arg-73	Arg-95	Arg-55
Lys-128	Lys-134	Lys-123	Lys-145	Lys-113
His-130	His-136	His-125	His-147	His-115
Lys-387	Lys-308	Lys-302	Lys-318	Lys-375
Gln-306	Gln-237	His-229	His-242	His-211
Asp-40	Asp-42	Asp-29	Asp-53	Asp-13
Asp-41	Gln-43	Asp-30	Asp-54	Asp-14
Asp-374	Asp-295	Asp-281	Asp-300	Asp-317
Gln-375	His-296	Asn-282	Asn-301	Asn-318
Asp-186*	−	−	−	−
Lys-187*	−	−	−	−
Phe-189*	−	−	−	−
Thr-300*	−	−	−	−
Tyr-378*	−	Arg-288	Ala-307	Leu-325
His-507*	−	His-405	Ser-403	−
Trp-307	Lys-238	Tyr-230	Glu-243	Trp-212