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Updated: Jul 11, 2026
10:34
Ligand Nano-cluster Arrays in a Supported Lipid Bilayer
Published on: April 23, 2017
The ligand-binding loops in the tunicate C-type lectin TC14 are rigid
S F Poget1, S M Freund, M J Howard
1MRC Centre for Protein Engineering, Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK.
Biochemistry
|September 12, 2001
Summary
C-type lectin-like domains, like TC14, exhibit intrinsic loop stability independent of calcium binding. This suggests inherent structural flexibility is crucial for ligand interactions in these common extracellular proteins.
Area of Science:
- Biochemistry
- Structural Biology
- Biophysics
Background:
- C-type lectin-like domains are prevalent in animal extracellular proteins, binding diverse ligands via extended surface loops.
- TC14, a C-type lectin from Polyandrocarpa misakiensis, specifically binds D-galactose, utilizing a calcium ion for coordination.
Purpose of the Study:
- To investigate the dynamic properties and structural flexibility of TC14.
- To determine the role of calcium ions in the structural stability and dynamics of TC14's loop regions.
- To understand the conformational changes associated with calcium binding and release.
Main Methods:
- Nuclear Magnetic Resonance (NMR) spectroscopy was employed, measuring 15N longitudinal and transverse relaxation rates.
- [1H-15N] heteronuclear NOEs were utilized to assess molecular dynamics.
- Chemical shift analysis compared the holo (calcium-bound) and apo (calcium-free) forms of TC14.
Main Results:
- TC14 exhibits minimal variations in relaxation rates and heteronuclear NOE values, indicating uniform rigidity across secondary structures and surface loops.
- Calcium binding does not significantly alter internal dynamics, suggesting intrinsic stability of the loop region.
- Loss of calcium induces minor structural changes localized to the binding site and propagates small changes without altering the overall fold, including cis-trans isomerization of proline 87.
Conclusions:
- The stability of C-type lectin-like domains' loop regions is intrinsic and not solely dependent on calcium coordination.
- Conformational flexibility, particularly around the calcium-binding site and cis-proline residues, is a key feature for ligand interactions.
- These findings provide insights into the mechanism of ligand binding for C-type lectin-like domains.
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