4P8W: The Crystal Structures Of Ykl-39 In The Presence Of Chitooligosaccharides (glcnac4) Were Solved To Resolutions Of 1.9 Angstrom

Four crystal structures of human YKL-39 were solved in the absence and presence of chitooligosaccharides. The structure of YKL-39 comprises a major (beta/alpha)8 triose-phosphate isomerase barrel domain and a small alpha + beta insertion domain. Structural analysis demonstrates that YKL-39 interacts with chitooligosaccharides through hydrogen bonds and hydrophobic interactions. The binding of chitin fragments induces local conformational changes that facilitate tight binding. Compared with other GH-18 members, YKL-39 has the least extended chitin-binding cleft, containing five subsites for sugars, namely (-3)(-2)(-1)(+1)(+2), with Trp-360 playing a prominent role in the sugar-protein interactions at the center of the chitin-binding cleft. Evaluation of binding affinities obtained from isothermal titration calorimetry and intrinsic fluorescence spectroscopy suggests that YKL-39 binds to chitooligosaccharides with Kd values in the micromolar concentration range and that the binding energies increase with the chain length. There were no significant differences between the Kd values of chitopentaose and chitohexaose, supporting the structural evidence for the five binding subsite topology. Thermodynamic analysis indicates that binding of chitooligosaccharide to YKL-39 is mainly driven by enthalpy.
PDB ID: 4P8WDownload
MMDB ID: 125210
PDB Deposition Date: 2014/4/1
Updated in MMDB: 2014/12
Experimental Method:
x-ray diffraction
Resolution: 1.87  Å
Source Organism:
Similar Structures:
Biological Unit for 4P8W: monomeric; determined by author and by software (PISA)
Molecular Components in 4P8W
Label Count Molecule
Protein (1 molecule)
Chitinase-3-like Protein 2(Gene symbol: CHI3L2)
Molecule annotation
Chemicals (9 molecules)
* Click molecule labels to explore molecular sequence information.

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