The ribF-ileS-lspA-fkpB-ispH operon in E. coli contains five genes that encode for various proteins. There are currently no known activators and repressors of this operon. The first gene, ribF, encodes for a bifunctional riboflavin kinase and FMN adenylyltransferase. In the cell, it is used to convert riboflavin to FMN, and then FMN to FAD. The second gene, ileS, encodes the isoleucine tRNA ligase or synthetase, which catalyzes the attachment of the amimno acid isoleucine onto its tRNA, forming a charged tRNA. The third gene, lspA, encodes a lipoprotein signal peptidase. This protein cleaves signal peptides from prolipoproteins, forming the mature lipoprotein, as well as a free signal peptide which is then degraded. The fourth gene, fkpB, encodes a peptidyl-prolyl cis-trans isomerase which works as an isomerase, and also posesses a chaperone activity, assisting in the folding of several ribosomal proteins. The final gene, ispH, encodes 1-hydroxy-2-methyl-2-(E)-butenyl 4-diphosphate (HMBPP) reductase. This protein catalyzes the conversion of HMBPP into both dimethylallyl diphosphate (DMAPP) and isopentenyl diphosphate (IPP) as part of the methylerythritol phosphate pathway involved in isoprenoid biosynthesis.

Operon: tRNA Synthetase & Peptidase References