Chemical characteristics of dimer interfaces in the legume lectin family

Elgavish, S Shaanan, B

S. Elgavish et B. Shaanan, Chemical characteristics of dimer interfaces in the legume lectin family, PROTEIN SCI, 10(4), 2001, pp. 753-761

42

INGLESE

Article

Biochemistry & Biophysics

PROTEIN SCIENCE

0961-8368 → ACNP

10

4

2001

753 - 761

ISI

0961-8368(200104)10:4<753:CCODII>2.0.ZU;2-3

The Erythrina corallaodendron lectin (EcorL) crystallizes in monoclinic and hexagonal crystal forms. Comparison of the newly determined hexagonal form (PDB code 1fyu) with the monoclinic form shows that the dimeric structure of EcorL reflects the inherent biological structure of the protein and is n ot an artifact of the crystal packing. To further understand the factors de termining the dimerization modes of legume lectins, EcorL, concanavalin A ( ConA), and Griffonia simplicifolia (GS4) were taken as representatives of t he three unique dimers found in the family. Six virtual homodimers were gen erated. The hydropathy, amino acid composition, and solvation energy were c alculated for all nine homodimers. Each of the three native dimers has a di stinct chemical composition. EcorL has: a dominant hydrophobic component, a nd ConA has a strong polar component, but in GS4 the three components contr ibute equally to the interface. This distribution pattern at the interface is unique to the native dimers and distinct from the partition observed in the virtual dimers. Amino acid composition of other members of the family t hat dimerize like EcorL or ConA maintain the same pattern of amino acids di stribution observed in EcorL and ConA. However, lectins that dimerize like GS4 do not show a particularly distinct distribution. In all cases, the cal culated solvation energy of the native dimer was lower than that of the vir tual dimers, suggesting that the observed mode of dimerization is the most stable organization for the given sequence and tertiary structure. The dime rization type cannot be predicted by sequence analysis.