Isolation and characterization of the ATP-binding cassette (ABC) transporter system genes from loofah witches' broom phytoplasma.
A clone containing a 3903 bp EcoRI-restriction fragment was obtained from a lambda(ZAP) genomic library of loofah witches' broom (LfWB) phytoplasma by plaque hybridization using a PCR fragment as a probe. Sequence analysis revealed that this fragment contained three open reading frames (ORFs). The deduced amino acid sequences of ORF 1 and ORF 2 showed a high homology with the ATP-binding proteins of the ABC transporter system genes of prokaryotes and eukaryotes, and encoded proteins with a molecular mass of 36 and 30 kDa, respectively. Based on amino acid sequence similarity, secondary structure, hydrophilicity and a signal peptide sequence at the N-terminus, we predicted that ORF 3 might encode a specific solute-binding prolipoprotein of the ABC transporter system with a molecular mass of 62 kDa. The cleavage site of this prolipoprotein signal peptide was similar to those of gram-positive bacteria. In addition to nutrient uptake, ABC transporter systems of bacteria also play a role in signal transduction, drug-resistance and perhaps virulence. The possible implications of the system to the survival and the pathogenesis of phytoplasma were discussed.
Huang
Chun-Lin
CL
Department of Life Science, Institute of Plant Biology, National Taiwan University, Taipei, Taiwan. wagtail@mail.nmns.edu.tw
Ho
Kuo-Chieh
KC
D020413:3' Untranslated Regions; D018528:ATP-Binding Cassette Transporters / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification*; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D004269:DNA, Bacterial / Q000737:chemistry; D015698:Genomic Library; D057927:Hydrophobic and Hydrophilic Interactions; D008969:Molecular Sequence Data; D008970:Molecular Weight; D016366:Open Reading Frames; D009876:Operon; D045582:Phytoplasma / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification*; D010944:Plants / Q000382:microbiology*; D021382:Protein Sorting Signals; D017433:Protein Structure, Secondary; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid
D020413:3' Untranslated Regions; D018528:ATP-Binding Cassette Transporters; D004269:DNA, Bacterial; D021382:Protein Sorting Signals