Volume 115, Issue 1, Pages 139-146 (July 1998) Three-dimensional structure of the major autoantigen in primary biliary cirrhosis  Mark J. Howard*, Christopher Fuller*, R.William Broadhurst*, Richard N. Perham*, Jian–Guo Tang*, Janet Quinn‡, Austin G. Diamond§, Stephen J. Yeaman‡  Gastroenterology  Volume 115, Issue 1, Pages 139-146 (July 1998) DOI: 10.1016/S0016-5085(98)70375-0 Copyright © 1998 American Gastroenterological Association Terms and Conditions

Fig. 1 Two-dimensional 15N-1H multiple quantum correlation spectrum of the inner human lipoyl domain. The spectrum was recorded at pH 6.5 and 308 K. The horizontal axis is proton chemical shift (parts per million relative to 2, 2-dimethyl-2-silapentane-5-sulfonic acid), and vertical axis is 15N chemical shift (parts per million relative to external NH3). Gastroenterology 1998 115, 139-146DOI: (10.1016/S0016-5085(98)70375-0) Copyright © 1998 American Gastroenterological Association Terms and Conditions

Fig. 2 Summary of the data used in the sequential assignment and secondary structure determination of the inner lipoyl domain of E2p from human PDC. The arrowheads define the direction of the strands with the dotted lines indicating strands that comprise one β sheet and the solid lines the other. The circles indicate the residues that showed slowly exchanging amide protons, stereospecifically assigned β protons, and coupling constants, which were incorporated in the structure calculations. Gastroenterology 1998 115, 139-146DOI: (10.1016/S0016-5085(98)70375-0) Copyright © 1998 American Gastroenterological Association Terms and Conditions

Fig. 3 1H, 1H NOE contact map for the inner human lipoyl domain showing the characteristic pattern for antiparallel β-sheet structure. Gastroenterology 1998 115, 139-146DOI: (10.1016/S0016-5085(98)70375-0) Copyright © 1998 American Gastroenterological Association Terms and Conditions

Fig. 4 Superposition of 26 conformers of the inner lipoyl domain of E2p from human PDC. The structures were generated by X-PLOR 3.1 from 1136 NOE restraints, 43 torsion angle restraints, and 28 hydrogen bond restraints. The relatively poorly defined lipoyl-lysine β turn (Asp49 to Ala51) and surface loop (Leu14 to Gly24) are at the top and the N- and C-terminal residues of the domain are at the bottom. The orientation is identical to the MOLSCRIPT representation in Figure 5. Gastroenterology 1998 115, 139-146DOI: (10.1016/S0016-5085(98)70375-0) Copyright © 1998 American Gastroenterological Association Terms and Conditions

Fig. 5 Stereo representation of the polypeptide fold (residues His9 to Val85) for the inner lipoyl domain of E2p from human PDC. The site of lipoylation (Lys50) is indicated, together with the type I β turn (black). The β sheet containing the immunologically important lipoyl-lysine residue is shown in dark grey; the β sheet containing the N- and C-terminal residues is shown in light grey. The figure was created using the program MOLSCRIPT. Gastroenterology 1998 115, 139-146DOI: (10.1016/S0016-5085(98)70375-0) Copyright © 1998 American Gastroenterological Association Terms and Conditions

Fig. 6 Amino acid sequence and secondary structure alignment of lipoyl domains. The position of each β strand is shown in bold and the amino acid sequence motif harboring the lipoyl-lysine residue at the tip of the β turn is italicized. AVE2o, A. vinelandii E2o; AVE2p-1, A. vinelandii; E2p innermost domain; BSE2p, B. stearothermophilus E2p; ECE2o, E. coli E2o; ECE2p-h, E. coli E2p hybrid domain; human E2p-1, human E2p inner domain (this study). For references, see text. Gastroenterology 1998 115, 139-146DOI: (10.1016/S0016-5085(98)70375-0) Copyright © 1998 American Gastroenterological Association Terms and Conditions