Expression and identification of the strA-strB gene pair from streptomycin-resistant Erwinia amylovora.
Deletions in either of the genes in the strA-strB gene pair of Erwinia amylovora plasmid pEa34 resulted in a dramatic decrease in streptomycin resistance (SmR), but SmR was restored to high levels by complementation. When strA and strB were cloned separately on a lacIq/Ptac-based expression vector in Escherichia coli, only the protein encoded by strA was produced. When a strong Shine-Dalgarno sequence was introduced and the start codon was located outside the double-stranded region of the stable stem-loop, the protein encoded by strB was produced. Biochemical analysis of the respective phosphorylated products demonstrated that strA and strB encoded aminoglycoside-3"-phosphotransferase (APH(3")-Ib) and aminoglycoside-6-phosphotransferase (APH(6)-Id), respectively. These data suggest that the high-level SmR in bacteria containing strA and strB is due to the combined action of the two enzymes.
Chiou
C S
CS
Department of Botany and Plant Pathology, Michigan State University, East Lansing 48824-1312.
Jones
A L
AL
D001483:Base Sequence; D003001:Cloning, Molecular; D004252:DNA Mutational Analysis; D004352:Drug Resistance, Microbial; D004885:Erwinia / Q000187:drug effects / Q000235:genetics*; D004926:Escherichia coli / Q000235:genetics; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial / Q000235:genetics*; D008969:Molecular Sequence Data; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics; D012045:Regulatory Sequences, Nucleic Acid / Q000235:genetics; D013307:Streptomycin / Q000494:pharmacology*
D012333:RNA, Messenger; D017853:Phosphotransferases (Alcohol Group Acceptor); C022680:streptomycin 6-kinase; C022679:streptomycin 3''-kinase; D013307:Streptomycin