Genome-wide analysis of lysine catabolism in bacteria reveals new connections with osmotic stress resistance

Autor(es)

Neshich, Izabella A. P. ^[1] ; Kiyota, Eduardo ^[2] ; Arruda, Paulo ^{[1, 2]}

Afiliação do(s) autor(es)

^[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

• Tipo de documento: Artigo Científico
• Fonte: ISME Journal; v. 7, n. 12, p. 2400-2410, DEC 2013.
• Citações Web of Science: 20

Resumo

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)

• Processo FAPESP: 12/00235-5 - Mecanismos de indução da via da sacaropina em células humanas
• Beneficiário: Izabella Agostinho Pena
• Modalidade de apoio: Bolsas no Brasil - Doutorado Direto
• Processo FAPESP: 10/50114-4 - O papel da via da sacaropina em diversos modelos biológicos
• Beneficiário: Paulo Arruda
• Modalidade de apoio: Auxílio à Pesquisa - Regular