Combining Crystallography and Hydrogen-Deuterium Exchange to Study Galectin-Ligand Complexes.
The physiological significance arising from translating information stored in glycans into cellular effects explains the interest in structurally defining lectin-carbohydrate recognition. The relatively small set of adhesion/growth-regulatory galectins in chicken makes this system attractive to study the origins of specificity and divergence. Cell binding by using glycosylation mutants reveals binding of the N-terminal domain of chicken galectin-8 (CG-8N) to α-2,3-sialylated and galactose-terminated glycan chains. Cocrystals with lactose and its 3'-sialylated derivative disclose Arg58 as a key contact for the carboxylic acid and differences in loop lengths to the three homodimeric chicken galectins. Monitoring hydrogen-deuterium exchange by mass spectrometry revealed an effective reduction of deuteration after ligand binding within the contact area. In addition, evidence for changes in solvent accessibility of amide protons beyond this site was obtained. Their detection, which highlights the sensor capacity of this technique, encourages systematic studies on galectins and beyond.
Departamento de Biología Físico-Química, Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu, 9 28040 Madrid (Spain).
Federico M
FM
Ruiz
Roche Diagnostics GmbH, Nonnenwald 2, 82377 Penzberg (Germany).
Ulrich
U
Gilles
Roche Diagnostics GmbH, Nonnenwald 2, 82377 Penzberg (Germany).
Ingo
I
Lindner
Institut für Physiologische Chemie, Tierärztliche Fakultät, Ludwig-Maximilians-Universität München, Veterinärstrasse 13, 80539 München (Germany). S.Andre@tiph.vetmed.uni-muenchen.de.
Sabine
S
André
Departamento de Biología Físico-Química, Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu, 9 28040 Madrid (Spain). romero@cib.csic.es.
Antonio
A
Romero
Roche Diagnostics GmbH, Nonnenwald 2, 82377 Penzberg (Germany). dietmar.reusch@roche.com.
Dietmar
D
Reusch
Institut für Physiologische Chemie, Tierärztliche Fakultät, Ludwig-Maximilians-Universität München, Veterinärstrasse 13, 80539 München (Germany).
Hans-Joachim
HJ
Gabius
X-ray crystallography; deuterium; glycosylation; lectins; sialylation