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Crystallographic studies of ligand binding by Zn-alpha(2)-glycoprotein

  • Lindsay McDermott
    ,
  • Silvia L. Delker
    ,
  • Anthony P. West
    ,
  • Malcolm W. Kennedy
    ,
  • Pamela J. Bjorkman
Research Output: Contribution to journal Article Peer-review

Sustainable Development Goals

  • SDG 3 - Good Health and Well-being
    SDG 3 Good Health and Well

Abstract

Zn-alpha2-glycoprotein (ZAG) is a 41 kDa soluble protein that is present in most bodily fluids. The previously reported 2.8 A crystal structure of ZAG isolated from human serum demonstrated the structural similarity between ZAG and class I major histocompatibility complex (MHC) molecules and revealed a non-peptidic ligand in the ZAG counterpart of the MHC peptide-binding groove. Here we present crystallographic studies to explore further the nature of the non-peptidic ligand in the ZAG groove. Comparison of the structures of several forms of recombinant ZAG, including a 1.95 A structure derived from ZAG expressed in insect cells, suggests that the non-peptidic ligand in the current structures and in the structure of serum ZAG is a polyethylene glycol (PEG), which is present in the crystallization conditions used. Further support for PEG binding in the ZAG groove is provided by the finding that PEG displaces a fluorophore-tagged fatty acid from the ZAG binding site. From these results we hypothesize that our purified forms of ZAG do not contain a bound endogenous ligand, but that the ZAG groove is capable of binding hydrophobic molecules, which may relate to its function.

Publication Information

Output type

Research Output: Contribution to journal Article Peer-review

Original language

English

Pages from-to (Number of pages)

Pages 205-213

Journal (Volume, Issue Number)

Journal of Structural Biology (Volume 148, Issue 2)

Publication milestones

  • Published - 19/05/2004

Publication status

Published - 19/05/2004

ISSN

1047-8477

External Publication IDs

  • handle.net: 10547/622681
  • Scopus: 5144219990

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