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Biochemical Characterization of Pathogenic Mutations in Human Mitochondrial tRNA‐Ala and Alanyl‐tRNA Synthetase
Author(s) -
Chihade Joseph,
Her Koua,
Steinbach Musetta,
France Katherine
Publication year - 2012
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.26.1_supplement.565.18
Subject(s) - transfer rna , aminoacylation , biology , wobble base pair , mutant , biochemistry , rna , genetics , microbiology and biotechnology , mitochondrion , gene
To understand the biochemical basis of pathogenic mutations in human mitochondrial (Hs mt) tRNA Ala and Hs mt alanyl‐tRNA synthetase (AlaRS), we have examined the enzyme's tRNA substrate recognition. Hs mt tRNA Ala lacks the G3:U70 wobble pair which is a conserved identity element in non‐mitochondrial alanine tRNAs. Aminoacylation by Hs mt AlaRS is insensitive to changes in the tRNA acceptor stem, including the G5:U68 wobble pair, and also insensitive to changes in the D‐stem‐loop, the T‐stem‐loop, and the anticodon loop. Aminoacylation rates are affected by changes in the variable loop‐anticodon stem region. Pathogenic tRNA Ala mutations apparently do not directly interfere with AlaRS substrate recognition, but may promote RNA misfolding. Initial characterization of mutant tRNAs using in‐line probing shows evidence of aberrant folds. We are currently investigating the effects of recently discovered (Götz, et al. , (2011) Am. J. Hum. Genet. 88, 635) pathogenic mutations in Hs mt AlaRS on RNA recognition and enzymatic function.