Crystal structure of the mouse galectin-4 N-terminal carbohydrate recognition domain

<aug><au><fnm>Veronika</fnm> <snm>Krejčiříková</snm></au>,<orf id="1"> <au><fnm> <au><fnm>Petr</fnm> <snm>Malý</snm></au>,<orf id="2"> <au><fnm>">Pavlína </fnm> <snm>Řezáčová</snm></au><orf id=""><orf id="1,3 and Jiří</fnm> <snm>Brynda</snm></au><orf id="1,3"><orf id="

<aff><oid id="1">Institute of Molecular Genetics, Academy of Sciences of the Czech Republic v.v.i., Flemingovo nám. 2, 166 37 Prague 6, Czech Republic, <cny>Czech Republic</cny></aff>

<aff><oid id="2">Institute of Biotechnology, Academy of Sciences of the Czech Republic, v.v.i., Vídeňská 1083, 142 20 Prague 4, <cny>Czech Republic</cny></aff>

<aff><oid id="3">Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic v.v.i., Flemingovo nám. 2., 166 10 Praha 6, <cny>Czech Republic</cny></aff></aug>. E-mail: brynda@img.cas.cz

Galectin-4, a member of the tandem repeat subfamily of galectins, participates in cell membrane interactions and plays an important role in cell adhesion, and modulation of immunity and malignity. Previously, we have reported on the oligosaccharide specificity of the mouse galectin-4 carbohydrate recognition domains (CRD). In this work, we further investigated the structure and binding properties of the N-terminal domain CRD1 and determined the crystal structure of CRD1 in complex with lactose at 2.1 Å resolution. We characterized lactose binding affinity by fluorescence measurements and identified two lactose binding sites: a high affinity site with the K_d value in micromolar range (K_d1 = 600 ± 70 µM) and a low affinity site with K_d2 of 28 ± 10 mM.

This study was supported by grants from the Grant Agency of the Czech Republic, reg. no. 203/09/0820 and 304/03/0090, by the grant 1M0505 from the Czech Ministry of Education, and by the institutional research projects AV0Z40550506, AV0Z50520514, and AV0Z50520701 awarded by the Academy of Sciences of the Czech Republic.