TY - JOUR
T1 - The 2.6 Å structure of antithrombin indicates a conformational change at the heparin binding site
AU - Skinner, Richard
AU - Abrahams, Jan Pieter
AU - Whisstock, James C.
AU - Lesk, Arthur M.
AU - Carrell, Robin W.
AU - Wardell, Mark R.
N1 - Funding Information:
This work was supported by the Wellcome Trust, the Medical Research Council and the British Heart Foundation. The authors thank the Station Masters at station 7.2 of the Daresbury Synchrotron Facility for their assistance during data collection. The atomic coordinates and structure factors of the structure have been deposited at the Brookhaven Protein Data Bank and have been assigned the codes 2ANT and R2ANTSF respectively.
PY - 1997/2/28
Y1 - 1997/2/28
N2 - The crystal structure of a dimeric form of intact antithrombin has been solved to 2.6 Å, representing the highest-resolution structure of an active, inhibitory serpin to date. The crystals were grown under microgravity conditions on Space Shuttle mission STS-67. The overall confidence in the structure, determined earlier from lower resolution data, is increased and new insights into the structure-function relationship are gained. Clear and continuous electron density is present for the reactive centre loop region P12 to P14 inserting into the top of the A-β-sheet. Areas of the extended amino terminus, unique to antithrombin and important in the binding of the glycosaminoglycan heparin, can now be traced further than in the earlier structures. As in the earlier studies, the crystals contain one active and one latent molecule per asymmetric unit. Better definition of the electron density surrounding the D-helix and of the residues implicated in the binding of the heparin pentasaccharide (Arg47, Lys114, Lys125, Arg129) provides an insight into the change of affinity of binding that accompanies the change in conformation. In particular, the observed hydrogen bonding of these residues to the body of the molecule in the latent form explains the mechanism for the release of newly formed antithrombin-protease complexes into the circulation for catabolic removal.
AB - The crystal structure of a dimeric form of intact antithrombin has been solved to 2.6 Å, representing the highest-resolution structure of an active, inhibitory serpin to date. The crystals were grown under microgravity conditions on Space Shuttle mission STS-67. The overall confidence in the structure, determined earlier from lower resolution data, is increased and new insights into the structure-function relationship are gained. Clear and continuous electron density is present for the reactive centre loop region P12 to P14 inserting into the top of the A-β-sheet. Areas of the extended amino terminus, unique to antithrombin and important in the binding of the glycosaminoglycan heparin, can now be traced further than in the earlier structures. As in the earlier studies, the crystals contain one active and one latent molecule per asymmetric unit. Better definition of the electron density surrounding the D-helix and of the residues implicated in the binding of the heparin pentasaccharide (Arg47, Lys114, Lys125, Arg129) provides an insight into the change of affinity of binding that accompanies the change in conformation. In particular, the observed hydrogen bonding of these residues to the body of the molecule in the latent form explains the mechanism for the release of newly formed antithrombin-protease complexes into the circulation for catabolic removal.
KW - 2.6 Å structure
KW - Antithrombin
KW - Dimer
KW - Heparin-pentasaccharide binding
KW - X-ray crystallography
UR - http://www.scopus.com/inward/record.url?scp=0031588685&partnerID=8YFLogxK
U2 - 10.1006/jmbi.1996.0798
DO - 10.1006/jmbi.1996.0798
M3 - Article
C2 - 9067613
AN - SCOPUS:0031588685
SN - 0022-2836
VL - 266
SP - 601
EP - 609
JO - Journal of Molecular Biology
JF - Journal of Molecular Biology
IS - 3
ER -