CLONING AND CHARACTERIZATION OF MITOCHONDRIAL METHIONYL-TRANSFER-RNA SYNTHETASE FROM A PATHOGENIC FUNGI CANDIDA-ALBICANS

A genomic sequence encoding mitochondrial methionyl-tRNA synthetase (M etRS) was determined from a pathogenic fungi Candida albicans. The gen e is distinct from that encoding the cytoplasmic MetRS. The encoded pr otein consists of 577 amino acids (aa) and contains the class I defini ng sequences in the N-terminal domain and the conserved anticodon-bind ing amino acid, Trp, in the C-terminal domain. This protein showed the highest similarity with the mitochondrial MetRSs of Saccharomyces cer evisiae and Shizosaccharomyces pombe. The mitochondrial MetRSs of thes e fungi were distinguished from their cytoplasmic forms. The protein l acks the zinc binding motif in the N-terminal domain and the C-termina l dimerization appendix that are present in MetRSs of several other sp ecies. Escherichia coli tRNA(Met) was a substrate for the encoded prot ein as determined by genetic complementation and in vitro aminoacylati on reaction. This cross-species aminoacylation activity suggests the c onservation of interaction mode between tRNA(Met) and MetRS. (C) 1998 Elsevier Science B.V. All rights reserved.