| Full text | |
| Author(s): |
Total Authors: 3
|
| Affiliation: | [1] Univ Estadual Campinas, UNICAMP, Ctr Biol Mol & Engn Genet, BR-13083875 Campinas, SP - Brazil
[2] Univ Estadual Campinas, UNICAMP, Inst Biol, Dept Genet & Evolucao, BR-13083875 Campinas, SP - Brazil
Total Affiliations: 2
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| Document type: | Journal article |
| Source: | ISME Journal; v. 7, n. 12, p. 2400-2410, DEC 2013. |
| Web of Science Citations: | 20 |
| Abstract | |
Lysine is catabolized via the saccharopine pathway in plants and mammals. In this pathway, lysine is converted to alpha-aminoadipic-delta-semialdehyde (AASA) by lysine-ketoglutarate reductase/saccharopine dehydrogenase (LKR/SDH); thereafter, AASA is converted to aminoadipic acid (AAA) by alpha-aminoadipic-delta-semialdehyde dehydrogenase (AASADH). Here, we investigate the occurrence, genomic organization and functional role of lysine catabolic pathways among prokaryotes. Surprisingly, only 27 species of the 1478 analyzed contain the lkr and sdh genes, whereas 323 species contain aasadh orthologs. A sdh-related gene, identified in 159 organisms, was frequently found contiguously to an aasadh gene. This gene, annotated as lysine dehydrogenase (lysdh), encodes LYSDH an enzyme that directly converts lysine to AASA. Pipecolate oxidase (PIPOX) and lysine-6-aminotransferase (LAT), that converts lysine to AASA, were also found associated with aasadh. Interestingly, many lysdh-aasadh-containing organisms live under hyperosmotic stress. To test the role of the lysine-to-AASA pathways in the bacterial stress response, we subjected Silicibacter pomeroyi to salt stress. All but lkr, sdh, lysdh and aasadh were upregulated under salt stress conditions. In addition, lysine-supplemented culture medium increased the growth rate of S. pomeroyi under high-salt conditions and induced high-level expression of the lysdh-aasadh operon. Finally, transformation of Escherichia coli with the S. pomeroyi lysdh-aasadh operon resulted in increased salt tolerance. The transformed E. coli accumulated high levels of the compatible solute pipecolate, which may account for the salt resistance. These findings suggest that the lysine-to-AASA pathways identified in this work may have a broad evolutionary importance in osmotic stress resistance. (AU) | |
| FAPESP's process: | 12/00235-5 - Mechanisms of saccharopine pathway induction in human cells |
| Grantee: | Izabella Agostinho Pena |
| Support Opportunities: | Scholarships in Brazil - Doctorate (Direct) |
| FAPESP's process: | 10/50114-4 - The role of saccharopine pathway in diverse biological models |
| Grantee: | Paulo Arruda |
| Support Opportunities: | Regular Research Grants |