1CAW

DETERMINATION OF THREE CRYSTAL STRUCTURES OF CANAVALIN BY MOLECULAR REPLACEMENT

Summary for 1CAW

• Entry DOI: 10.2210/pdb1caw/pdb
• Descriptor: CANAVALIN (2 entities in total)
• Functional Keywords: seed storage protein
• Biological source: Canavalia ensiformis (jack bean); More
• Total number of polymer chains: 2
• Total formula weight: 41609.75

Authors

Ko, T-P.,Ng, J.D.,Day, J.,Greenwood, A.,McPherson, A. (deposition date: 1993-06-02, release date: 1993-10-31, Last modification date: 2024-02-07)

Primary citation

Ko, T.P.,Ng, J.D.,Greenwood, A.,McPherson, A.
Determination of three crystal structures of canavalin by molecular replacement.
Acta Crystallogr.,Sect.D, 49:478-489, 1993

PubMed Abstract: Canavalin, the major reserve protein of the jack bean, was obtained in four different crystal forms. From the structure determined by multiple isomorphous replacement in a hexagonal unit cell, the structures of three other crystals were determined by molecular replacement. In two cases, the rhombohedral and cubic crystals, placement was facilitated by coincidence of threefold molecular symmetry with crystallographic operators. In the orthorhombic crystal the canavalin trimer was the asymmetric unit. The rhombohedral, orthorhombic and cubic crystal structures were subsequently refined using a combination of several approaches with resulting R factors of 0.194, 0.185 and 0.211 at resolutions of 2.6, 2.6 and 2.3 A, respectively. Variation in the conformation of the molecule from crystal to crystal was small with an r.m.s. deviation in Calpha positions of 0.89 A. Packing is quite different among crystal forms but lattice interactions appear to play little role in the conformation of the molecule. Greatest variations in mean position are for those residues that also exhibit the greatest thermal motion. Crystal contacts in all crystals are mediated almost exclusively by hydrophilic side chains, and three to six intermolecular salt bridges per protein subunit are present in each case.

PubMed: 15299507
DOI: 10.1107/S0907444993004056

Experimental method

X-RAY DIFFRACTION (2.6 Å)