Molecular characterization of a rab-related small GTP binding protein cDNA from rice (Oryza sativa L. IR-36).
To study physiological roles of plant small GTP binding proteins, we isolated a cDNA clone (ORrab2) encoding the rab-related small GTP binding protein from rice (Oryza sativa L. IR-36) by using human cDNA rab2 as a probe. The deduced amino acid sequence of the ORrab2 gene shared all the conserved regions, important for GTPase/GTP binding activities, with those of other small GTP binding proteins. ORrab2 is a 1028 bp long cDNA, encodes a 23.2 kDa protein which shows 85.2% similarity on the amino acid sequence level to the Hrab2 protein, and was used as a probe. Through Southern and Northern blot analyses, we found that ORrab2 is a single copy gene and actively expressed at the stages of cell division and elongation. We investigated GTP binding abilities by a filter assay procedure. Deletion of a binding motif, GDTGVGKS, within an ORrab2 protein showed a significant decrease of GTP binding affinity, suggesting its important role in nucleotide binding.
Kim
H Y
HY
Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Chinju, Korea.
Seo
H S
HS
Jeong
J Y
JY
Lee
S Y
SY
Cho
M J
MJ
Bahk
J D
JD
D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics*; D018744:DNA, Plant / Q000235:genetics*; D004926:Escherichia coli / Q000235:genetics; D019204:GTP-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D015870:Gene Expression; D017343:Genes, Plant; D006160:Guanosine Triphosphate / Q000378:metabolism; D006801:Humans; D008969:Molecular Sequence Data; D012275:Oryza / Q000235:genetics* / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D020693:rab2 GTP-Binding Protein
D018076:DNA, Complementary; D018744:DNA, Plant; D010940:Plant Proteins; D006160:Guanosine Triphosphate; D019204:GTP-Binding Proteins; D020693:rab2 GTP-Binding Protein