5NM1

Chicken GRIFIN (crystallisation pH: 6.2)

Summary for 5NM1

• Entry DOI: 10.2210/pdb5nm1/pdb
• Related PRD ID: PRD_900008
• Descriptor: Galectin, beta-D-galactopyranose-(1-4)-alpha-D-glucopyranose (3 entities in total)
• Functional Keywords: galectin related protein, sugar binding protein
• Biological source: Gallus gallus (Chicken)
• Total number of polymer chains: 4
• Total formula weight: 66190.83

Authors

Ruiz, F.M.,Romero, A. (deposition date: 2017-04-05, release date: 2018-02-14, Last modification date: 2024-01-17)

Primary citation

Ruiz, F.M.,Gilles, U.,Ludwig, A.K.,Sehad, C.,Shiao, T.C.,Garcia Caballero, G.,Kaltner, H.,Lindner, I.,Roy, R.,Reusch, D.,Romero, A.,Gabius, H.J.
Chicken GRIFIN: Structural characterization in crystals and in solution.
Biochimie, 146:127-138, 2018

PubMed Abstract: Despite its natural abundance in lenses of vertebrates the physiological function(s) of the galectin-related inter-fiber protein (GRIFIN) is (are) still unclear. The same holds true for the significance of the unique interspecies (fish/birds vs mammals) variability in the capacity to bind lactose. In solution, ultracentrifugation and small angle X-ray scattering (at concentrations up to 9 mg/mL) characterize the protein as compact and stable homodimer without evidence for aggregation. The crystal structure of chicken (C-)GRIFIN at seven pH values from 4.2 to 8.5 is reported, revealing compelling stability. Binding of lactose despite the Arg71Val deviation from the sequence signature of galectins matched the otherwise canonical contact pattern with thermodynamics of an enthalpically driven process. Upon lactose accommodation, the side chain of Arg50 is shifted for hydrogen bonding to the 3-hydroxyl of glucose. No evidence for a further ligand-dependent structural alteration was obtained in solution by measuring hydrogen/deuterium exchange mass spectrometrically in peptic fingerprints. The introduction of the Asn48Lys mutation, characteristic for mammalian GRIFINs that have lost lectin activity, lets labeled C-GRIFIN maintain capacity to stain tissue sections. Binding is no longer inhibitable by lactose, as seen for the wild-type protein. These results establish the basis for detailed structure-activity considerations and are a step to complete the structural description of all seven members of the galectin network in chicken.

PubMed: 29248541
DOI: 10.1016/j.biochi.2017.12.003

Experimental method

X-RAY DIFFRACTION (2.099 Å)