Structure of a legume lectin from the bark of Robinia pseudoacacia and itscomplex with N-acetylgalactosamine

The structure of the bark lectin RPbAI (isoform A(4)) from Robinia pseudoac acia has been determined by protein crystallography both in the free form a nd complexed with N-acetylgalactosamine. The free form is refined at 1.80 A ngstrom resolution to an R-factor of 18.9% whereas the complexed structure has an R-factor of 19.7% at 2.05 Angstrom resolution. Both structures are c ompared to each other and to other available legume lectin structures. The polypeptide chains of the two structures exhibit the characteristic legume lectin tertiary fold. The quaternary structure resembles that of the Phaseo lus vulgaris lectin, the soybean agglutinin, and the Dolichos biflorus lect in, but displays some unique features leading to the extreme stability of t his lectin. Proteins 2001;44:470-478. (C) 2001 Wiley-Liss, Inc.