2ENR

CO-CRYSTALS OF DEMETALLIZED CONCANAVALIN A WITH CADMIUM HAVING A CADMIUM ION BOUND IN BOTH THE S1 SITE AND THE S2 SITE

Summary for 2ENR

• Entry DOI: 10.2210/pdb2enr/pdb
• Descriptor: CONCANAVALIN A, CADMIUM ION (3 entities in total)
• Functional Keywords: concanavalin a, plant lectin, carbohydrate binding, metal binding, cadmium, lectin
• Biological source: Canavalia ensiformis (jack bean)
• Total number of polymer chains: 1
• Total formula weight: 25847.21

Authors

Bouckaert, J.,Loris, R.,Wyns, L. (deposition date: 1998-07-14, release date: 1999-02-16, Last modification date: 2024-05-22)

Primary citation

Bouckaert, J.,Loris, R.,Wyns, L.
Zinc/calcium- and cadmium/cadmium-substituted concanavalin A: interplay of metal binding, pH and molecular packing.
Acta Crystallogr.,Sect.D, 56:1569-1576, 2000

PubMed Abstract: The crystal structures of cadmium/cadmium and zinc/calcium concanavalin A (con A) at pH 5.0 and pH 6.15, respectively, were determined. The structure of cadmium/cadmium con A confirms that the secondary Cd(2+)-binding site S3 is empty at pH 5. The metal-binding sites S1 and S2 are only very slightly affected by the substitution with cadmium. On the other hand, S1 and S2 and most of the protein surface of zinc/calcium con A at pH 6.15 differ from other fully metal-bound and carbohydrate-free structures. Most of these structural differences at the protein surface are a result of the interplay between metal binding, protonation and crystal packing. This interplay is expressed by relative rotations and translations of the con A units in alternative crystal packings and participation in space-group conversions inside crystals in situ. The particular crystal packing of zinc/calcium con A creates a novel zinc-binding site S4. The Zn(2+) ion in S4 ligates two aspartates from one tetramer and a histidine from a symmetry-related tetramer.

PubMed: 11092923
DOI: 10.1107/S0907444900013342

Experimental method

X-RAY DIFFRACTION (2.35 Å)