99A-33 |
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L. TU, Food Science, University of Missouri - Columbia, 256 William Stringer Wing, Eckles Hall, University of Missouri, Columbia, MO 65211, F. Du, Genome Sequencing Center, Washington University School of Medicine, 4444 Forest Park Boulevard, St Louis, MO 63108, and A. Mustapha, Department of Food Science, University of Missouri, 256 Eckles Hall - Stringer Wing, Columbia, MO 65211. Genomic evolution has been profoundly influenced by DNA transposition. Transposases are multifunctional enzymes that specifically recognize transposon ends and catalyze the breakage and joining reactions, leading to transfer of those ends to the target DNA. Understanding the characteristics of these proteins is central to understanding the molecular basis of transposition. However, no data is available regarding transposases in bifidobacteria, which is an important probiotic organism in the dairy and functional foods industry. Our objectives were to clone and sequence the transposase gene from Bifidobacterium infantis . A genomic DNA library of B. infantis 15702 was constructed in l phage and 5 positive clones were further analyzed. Sequencing was performed by primer walking from both directions of the cloned DNA. Sequence results revealed the presence of one open reading frames (ORF) spanning 1016 bp on a 3277-bp cloned DNA fragment. The ORF started with the ATG codon at position 1453 and terminated with the TGA stop codon at position 2469. The deduced amino acid sequence consists of 339 residues. Comparative analysis of the predicted amino acid sequence with the protein sequence databases revealed that the highest identity, 35.0%, was between the transposases of B. infantis 15702 and Deinococcus radiodurans (strain R1). There are also strong homologies between the transposase of B. infantis 15702 and that of Nostoc sp. strain PCC 7120 plasmid pCC7120 alpha and Streptomyces coelicolor (34.2% and 33.8%, respectively). Knowledge of the structure of the bifidobacterial transposase gene will provide the basis for genetic approaches that will lead to a better understanding of the genomic evolution of this important organism.
Session 99A, Biotechnology: General
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