Organ-specific occurrence and expression of the isoforms of nonspecific lipid transfer protein in castor bean seedlings, and molecular cloning of a full-length cDNA for a cotyledon-specific isoform.
Four kinds of nonspecific lipid transfer proteins (nsLTP) were purified from different organs of castor bean (Ricinus communis L.) seedlings. Amino acid compositions and amino-terminal sequences of the four nsLTPs were determined and compared with those of castor bean isoforms, nsLTP-A, -B, and -C, previously reported [Takishima et al. (1986) Biochim. Biophys. Acta 870, 248-255; Takishima et al. (1988) Eur. J. Biochem. 177, 241-249]. Two isoforms from the cotyledons were identified as nsLTP-A and -C, one isoform from the endosperms as nsLTP-B, and the other was a new isoform from the axes. This new isoform was named nsLTP-D and its amino acid sequence was determined. These results demonstrated organ-specific occurrence of the nsLTP isoforms in castor bean seedlings. The isoforms nsLTP-A, -B, -C, and -D showed similar transfer activity not only for phosphatidylcholine and phosphatidylethanolamine but also for monogalactosyldiacylglycerol, although the homology among their amino acid sequences ranged from 70 to 30%. Two cDNA clones (pnsLTP-C and pnsLTP-D) for nsLTPs of castor bean seedlings were isolated and sequenced. pnsLTP-C was the cDNA clone for nsLTP-C expressed in the cotyledons, and pnsLTP-D was that for nsLTP-D in the axis. A coupled in vitro transcription-translation analysis of both cDNA clones revealed that pnsLTP-C encodes the full-length of nsLTP-C precursor (pro-nsLTP-C), while pnsLTP-D encodes a part of nsLTP-D precursor. PronsLTP-C contained a 24-amino acid pre-sequence preceding the mature nsLTP-C (92 amino acids).(ABSTRACT TRUNCATED AT 250 WORDS)
Tsuboi
S
S
Department of Biology, College of Arts and Sciences, University of Tokyo.
Suga
T
T
Takishima
K
K
Mamiya
G
G
Matsui
K
K
Ozeki
Y
Y
Yamada
M
M
D000595:Amino Acid Sequence; D052179:Antigens, Plant; D001483:Base Sequence; D002352:Carrier Proteins / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification; D002367:Ricinus communis / Q000737:chemistry* / Q000235:genetics; D003001:Cloning, Molecular; D004247:DNA / Q000302:isolation & purification*; D007536:Isomerism; D008969:Molecular Sequence Data; D009928:Organ Specificity; D010940:Plant Proteins / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification; D010947:Plants, Toxic; D014176:Protein Biosynthesis; D012639:Seeds / Q000235:genetics*; D013329:Structure-Activity Relationship; D014158:Transcription, Genetic
D052179:Antigens, Plant; D002352:Carrier Proteins; D010940:Plant Proteins; C511920:lipid transfer proteins, plant; D004247:DNA