tailieunhanh - Báo cáo khoa học: Many fructosamine 3-kinase homologues in bacteria are ribulosamine⁄erythrulosamine 3-kinases potentially involved in protein deglycation

The purpose of this work was to identify the function of bacterial homo-logues of fructosamine 3-kinase (FN3K), a mammalian enzyme responsible for the removal of fructosamines from proteins. FN3K homologues were identified in 200 (. 27%) of the sequenced bacterial genomes. | ễFEBS Journal Many fructosamine 3-kinase homologues in bacteria are ribulosamine erythrulosamine 3-kinases potentially involved in protein deglycation Rita Gemayel Juliette Fortpied Rim Rzem Didier Vertommen Maria Veiga-da-Cunha and Emile Van Schaftingen Université Catholique de Louvain de Duve Institute Brussels Belgium Keywords deglycation erythrose 4-phosphate fructosamine glycation ribose 5-phosphate Correspondence E. Van Schaftingen UCL 7539 Avenue Hippocrate 75 B-1200 Brussels Belgium Fax 32 27 647598 Tel 32 27 647564 E-mail vanschaftingen@ Received 11 April2007 revised 15 June 2007 accepted 18 June 2007 doi The purpose of this work was to identify the function of bacterial homologues of fructosamine 3-kinase FN3K a mammalian enzyme responsible for the removal of fructosamines from proteins. FN3K homologues were identified in w 200 . w27 of the sequenced bacterial genomes. In 11 of these genomes from phylogenetically distant bacteria the FN3K homologue was immediately preceded by a low-molecular-weight protein-tyro-sine-phosphatase LMW-PTP homologue which is therefore probably functionally related to the FN3K homologue. Five bacterial FN3K homologues from Escherichia coli Enterococcus faecium Lactobacillus plantarum Staphylococcus aureus and Thermus thermophilus were overexpressed in E. coli purified and their kinetic properties investigated. Four were ribu-losamine erythrulosamine 3-kinases acting best on free lysine and cadaverine derivatives but not on ribulosamines bound to the alpha amino group of amino acids. They also phosphorylated protein-bound ribulosamines or erythrulosamines but not protein-bound fructosamines therefore having properties similar to those of mammalian FN3K-related protein. The E. coli FN3K homologue YniA was inactive on all tested substrates. The LMW-PTP of T. thermophilus which forms an operon with an FN3K homologue and an LMW-PTP of S. aureus PtpA were overexpressed in E. coli .