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Chloroplast heat shock protein Cpn60 from Chlamydomonas reinhardtii exhibits a novel function as a group II intron‐specific RNA‐binding protein
Author(s) -
Balczun Carsten,
Bunse Astrid,
Schwarz Christian,
Piotrowski Markus,
Kück Ulrich
Publication year - 2006
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2006.07.030
Subject(s) - chlamydomonas reinhardtii , intron , biology , rna splicing , rna , rna binding protein , gene , biochemistry , chloroplast , microbiology and biotechnology , mutant
Intron‐binding proteins in eukaryotic organelles are mainly encoded by the nuclear genome and are thought to promote the maturation of precursor RNAs. Here, we present a biochemical approach that enable the isolation of a novel nuclear‐encoded protein from Chlamydomonas reinhardtii showing specific binding properties to organelle group II intron RNA. Using FPLC chromatography of chloroplast protein extracts, a 61‐kDa RNA‐binding protein was isolated and then tentatively identified by mass spectrometry as the chloroplast heat shock protein Cpn60. Heterologous Cpn60 protein was used in RNA protein gel mobility shift assays and revealed that the ATPase domains of Cpn60 mediates the specific binding of two group II intron RNAs, derived from the homologous chloroplast psaA gene and the heterologous mitochondrial LSU rRNA gene. The function of Cpn60 as a general organelle splicing factor is discussed.