Premium
Structural comparison of protiated, H/D‐exchanged and deuterated human carbonic anhydrase IX
Author(s) -
Koruza K.,
Lafumat B.,
Nyblom M.,
Mahon B. P.,
Knecht W.,
McKenna R.,
Fisher S. Z.
Publication year - 2019
Publication title -
acta crystallographica section d
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.374
H-Index - 138
ISSN - 2059-7983
DOI - 10.1107/s2059798319010027
Subject(s) - crystal structure , chemistry , crystallography , active site , carbonic anhydrase ii , hydrogen–deuterium exchange , stereochemistry , carbonic anhydrase , enzyme , biochemistry , hydrogen , organic chemistry
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 IX SV ; 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 IX SV for crystallographic studies and their structural comparison are described. Four CA IX SV 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 IX SV 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 IX SV for neutron protein crystallography.