Structural comparison of protiated, H/D-exchanged and deuterated human carbonic anhydrase IX

Research output: Contribution to journalArticle


Human carbonic anhydrase IX (CA IX) expression is upregulated in hypoxic solid tumours, promoting cell survival and metastasis. This observation has made CA IX a target for the development of CA isoform-selective inhibitors. To enable structural studies of CA IX-inhibitor complexes using X-ray and neutron crystallography, a CA IX surface variant (CA IXSV; the catalytic domain with six surface amino-acid substitutions) has been developed that can be routinely crystallized. Here, the preparation of protiated (H/H), H/D-exchanged (H/D) and deuterated (D/D) CA IXSV for crystallographic studies and their structural comparison are described. Four CA IXSV X-ray crystal structures are compared: two H/H crystal forms, an H/D crystal form and a D/D crystal form. The overall active-site organization in each version is essentially the same, with only minor positional changes in active-site solvent, which may be owing to deuteration and/or resolution differences. Analysis of the crystal contacts and packing reveals different arrangements of CA IXSV compared with previous reports. To our knowledge, this is the first report comparing three different deuterium-labelled crystal structures of the same protein, marking an important step in validating the active-site structure of CA IXSV for neutron protein crystallography.


External organisations
  • University of Florida
  • AstraZeneca, Sweden
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Structural Biology


  • Antigens, Neoplasm/chemistry, Carbonic Anhydrase IX/chemistry, Catalytic Domain, Cloning, Molecular, Crystallography, X-Ray/methods, Deuterium, Escherichia coli/genetics, Humans, Models, Molecular
Original languageEnglish
Pages (from-to)895-903
JournalActa Crystallographica Section D: Structural Biology
Issue numberPt 10
Publication statusPublished - 2019 Oct 1
Publication categoryResearch

Bibliographic note

open access.