A lectin and a lectin-related protein are the two most prominent proteins in the bark of yellow wood (Cladrastis lutea).
Using a combination of cDNA cloning and protein purification it is demonstrated that bark of yellow wood (Cladrastis lutea) contains two mannose/glucose binding lectins and a lectin-related protein which is devoid of agglutination activity. One of the lectins (CLAI) is the most prominent bark protein. It is built up of four 32 kDa monomers which are post-translationally cleaved into a 15 kDa and a 17 kDa polypeptide. The second lectin (CLAII) is a minor protein, which strongly resembles CLAI except that its monomers are not cleaved into smaller polypeptides. Molecular cloning of the Cladrastis lectin family revealed also the occurrence of a lectin-related protein (CLLRP) which is the second most prominent bark protein. Although CLLRP shows sequence homology to the true lectins, it is devoid of carbohydrate binding activity. Molecular modelling of the three Cladrastis proteins has shown that their three-dimensional structure is strongly related to the three-dimensional models of other legume lectins and, in addition, revealed that the presumed carbohydrate binding site of CLLRP is disrupted by an insertion of three extra amino acids. Since it is demonstrated for the first time that a lectin and a non-carbohydrate binding lectin-related protein are the two most prominent proteins in the bark of a tree, the biological meaning of their simultaneous occurrence is discussed.
Laboratory for Phytopathology and Plant Protection, Katholieke Universiteit Leuven, Belgium.
E J
EJ
Van Damme
A
A
Barre
V
V
Bemer
P
P
Rougé
F
F
Van Leuven
W J
WJ
Peumans
D000595:Amino Acid Sequence; D000818:Animals; D001681:Biological Assay; D015152:Blotting, Northern; D002478:Cells, Cultured; D002852:Chromatography, Ion Exchange; D003001:Cloning, Molecular; D004591:Electrophoresis, Polyacrylamide Gel; D037102:Lectins / Q000096:biosynthesis* / Q000737:chemistry / Q000302:isolation & purification; D008213:Lymphocyte Activation; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010802:Phylogeny; D037121:Plant Lectins; D010940:Plant Proteins / Q000096:biosynthesis* / Q000737:chemistry / Q000302:isolation & purification; D011499:Protein Processing, Post-Translational; D017433:Protein Structure, Secondary; D017386:Sequence Homology, Amino Acid; D014197:Trees / Q000235:genetics / Q000378:metabolism*
C097406:LRPCL protein, Cladrastis lutea; D037102:Lectins; D037121:Plant Lectins; D010940:Plant Proteins; C097405:mannose-glucose-binding lectin, Cladrastis lutea