Purification and characterization of a mannan-binding lectin specifically expressed in corms of saffron plant (Crocus sativus L.).
Despite the economical interest of Crocus sativus, its biochemistry has been poorly studied. Herein, we have isolated a lectin present in saffron corm by gel-filtration, anion-exchange, and reversed-phase chromatography. One- and two-dimensional PAGE, MALDI-MS, and N-terminal amino acid sequence analyses indicated that the native protein forms noncovalently linked aggregates of about 80 kDa apparent molecular mass, mainly composed of two charged heterogeneous (pI's, 6.69-6.93) basic subunits of approximately 12 kDa. Their N-terminal sequences shared 25% similarity and were homologous to the N- and C-terminal domains of monocotyledonous mannose-binding lectins, respectively. An additional polypeptide of around 28 kDa apparent molecular mass was also detected, probably corresponding to a precursor processed into two mature subunits. In addition, the N-terminal domain subunit exhibited 56% similarity with curculin, a sweet protein with taste-modifying activity. The native lectin specifically interacts with a yeast mannan and is a major corm protein specifically expressed in this organ.
Escribano
J
J
Grupo de Genética y Biotecnología, Departamento de Ciencia y Tecnología Agroforestal-UCLM, E.T.S. Ingenieros Agrónomos, Campus Universitario s/n, 02071 Albacete, Spain.
Rubio
A
A
Alvarez-Ortí
M
M
Molina
A
A
Fernández
J A
JA
D000595:Amino Acid Sequence; D002352:Carrier Proteins / Q000302:isolation & purification*; D037222:Collectins; D019668:Liliaceae / Q000378:metabolism*; D008969:Molecular Sequence Data; D008970:Molecular Weight; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
D002352:Carrier Proteins; D037222:Collectins