The structural characteristics and function analysis of the mobile genomic islands flanked by isocitrate dehydrogenase genes in Escherichia coli and Salmonella enterica

摘要

Eleven genomic islands (GIs) flanked by isocitrate dehydrogenase genes are determined in Escherichia coli and Salmonella enterica. These GIs have at least one mobile gene, such as integrase gene, transposase gene or recombinase gene. Through annotation of internal genes, these GIs are related to lambda prophage. The excisionase gene is associated with the mobile gene in some GIs. An ABC transporter, namely, sitABCD operon, is existed in some GIs and may uptake Fe~(2+) and Mn~(2+). Mn~(2+) is a second cofactor and an essential activator of the isocitrate dehydrogenase. The cleavage site of functional lambda integrase is 5'-TGCTGCGCCA-3' in direct repeats at 3'-end of icd gene.The truncated lambda integrases (ECP_1132 and ECP_ 1135) are inactive because the transposon inserted the integrase gene by 5'-CCTGG-3'. This Fe~(2+)/Mn~(2+) transport operon is predicted that is a recent product of horizontal gene transfer in E. coli because this operon is also existed in S. enterica and is not in a mobile GIs.