tailieunhanh - Báo cáo khoa học: Alternative splicing produces an H-protein with better substrate properties for the P-protein of glycine decarboxylase

Several thousand plant genes are known to produce multiple transcripts, but the precise function of most of the alternatively encoded proteins is not known. Alternative splicing has been reported for the H-protein subunit of glycine decarboxylase in the genus Flaveria. H-protein has no catalytic activity itself but is a substrate of the three enzymatically active subunits, P-, T- and L-protein. | ỊFEBS Journal Alternative splicing produces an H-protein with better substrate properties for the P-protein of glycine decarboxylase Dirk Hasse1 Stefan Mikkat2 Martin Hagemann1 and Hermann Bauwe1 1 Department of Plant Physiology University of Rostock Germany 2 Core Facility Proteome Analysis MedicalFaculty University of Rostock Germany Keywords alternative splicing glycine decarboxylase H-protein photorespiration Correspondence H. Bauwe Department of Plant Physiology University of Rostock Albert-Einstein-StraBe 3 D-18059 Rostock Germany Fax 49 381 498 6112 Tel 49 381 498 6110 E-mail Website http pflanzenphysiologie Received 7 July 2009 revised 5 September 2009 accepted 25 September 2009 doi Several thousand plant genes are known to produce multiple transcripts but the precise function of most of the alternatively encoded proteins is not known. Alternative splicing has been reported for the H-protein subunit of glycine decarboxylase in the genus Flaveria. H-protein has no catalytic activity itself but is a substrate of the three enzymatically active subunits P- T- and L-protein. In C4 species of Flaveria two H-proteins originate from single genes in an organ-dependent manner. Here we report on differences between the two alternative H-protein variants with respect to their interaction with the glycine-decarboxylating subunit P-protein. Steady-state kinetic analyses of the alternative Flaveria H-proteins and artificially produced alternative Arabidopsis H-proteins using either pea mitochondrial matrix extracts or recombinant cyanobacterial P-protein consistently demonstrate that the alternative insertion of two alanine residues at the N-ter-minus of the H-protein elevates the activity of P-protein by 20 in vitro and could promote glycine decarboxylase activity in vivo. Introduction Several thousand plant genes are known to produce multiple transcripts but the precise function of