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U of I Only 9780591199246 AAI9712359 Shaw, Paul D. Liu, Lixia 2011-05-07T12:45:30Z 2011-05-07T12:45:30Z 10000-01-01 1996 The relationship between the biosynthesis of tabtoxinine-$\beta$-lactam $\rm(T\beta L)$ and lysine by Pseudomonas syringae pv. tabaci strain BR2.024 (PTBR2.024) was investigated. A Tn5 mutant of PTBR2.024 showing diaminopimelate auxotrophy and $\rm T\beta L$-deficiency was isolated. Complementation results indicate that a region containing single open reading frame (ORF) is able to complement both mutant phenotypes. The deduced amino acid sequence of the ORF has a significant sequence homology to known dapB gene products, a lysine biosynthetic enzyme of bacteria. Furthermore, the ORF is able to complement an E. coli dapB mutant. The ORF was designated dapB. These results suggest that L-2,3,4,5-tetrahydrodipicolinate is a common intermediate in lysine and $\rm T\beta L$ biosynthesis. A gene with a predicted product having an amino acid sequence homologous to known dapD gene products, another lysine biosynthetic enzyme in bacteria, was also identified. Complementation tests, in vitro transcription/translation analysis and enzymatic assays indicate that the dapD-like gene is able to encode a product with THDPA N-succinyltransferase (THDPA-ST) activity in E. coli. However, no THDPA-ST activity was detected in PTBR2.024 and a mutation in the dapD-like gene has no effect on lysine biosynthesis of strain PTBR2.024. These results indicate that the dapD-like gene is not involved in lysine biosynthesis in PTBR2.024. The mutation, however, caused a 50 percent reduction in $\rm T\beta L$ production. This suggests that the dapD-like gene may be involved in $\rm T\beta L$ biosynthesis. The dapD-like gene was named tabB. Enzymatic assay results indicate that PTBR2.024 uses an acetyl pathway for lysine biosynthesis. This is the first report of a Gram-negative bacterium utilizing that pathway. An gene, ORF$\rm\sb{L}$, able to complement the dapD mutant $\beta$274 also was isolated from the PTBR2.024 genomic library. A mutant with an insertion in ORF$\rm\sb{L}$ produced as much T$\beta$L as parent strain. However, the mutant had reduced growth rate in minimal medium. The growth rate was restored by addition of lysine in minimal medium. Complementation analyses indicate that the ORF$\rm\sb{L}$ mutant phenotype was due to a polar effect. This suggests that the ORF$\rm\sb{L}$ may not be involved in either lysine or tabtoxin biosynthesis. Made available in DSpace on 2011-05-07T12:45:30Z (GMT). No. of bitstreams: 2 license.txt: 4922 bytes, checksum: 910b249b4beec47e7ab768910c8f966f (MD5) 9712359.pdf: 4202813 bytes, checksum: b7e83edefe978ec62f5941a48824423b (MD5) Previous issue date: 1996 Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding (hding2@illinois.edu) on 2011-05-07T14:45:22Z Item is restricted indefinitely. Restriction data tranferred 2014-07-01T11:20:05-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: ETDs are only available to UIUC Users without author permission ETDs are only available to UIUC Users without author permission (UMI)AAI9712359 http://hdl.handle.net/2142/20655 eng Copyright 1996 Liu, Lixia Biology, Molecular Biology, Microbiology Characterization of genes involved in tabtoxinine-beta-lactam and lysine biosynthesis by Pseudomonas syringae pv. tabaci strain PTBR2.024 text Crop Sciences Crop Sciences University of Illinois at Urbana-Champaign Dissertation Ph.D.