TY - JOUR
T1 - A Motif in Human Histidyl-tRNA Synthetase Which Is Shared among Several Aminoacyl-tRNA Synthetases Is a Coiled-coil That Is Essential for Enzymatic Activity and Contains the Major Autoantigenic Epitope
AU - Raben, Nina
AU - Nichols, Ralph
AU - Dohlman, Jan
AU - McPhie, Peter
AU - Sridhar, Vaidehi
AU - Hyde, Craig
AU - Leff, Richard
AU - Plotz, Paul
PY - 1994/9/30
Y1 - 1994/9/30
N2 - In myositis, disease-specific autoantibodies may be directed against an aminoacyl-tRNA synthetase, usually histidyl-tRNA synthetase. To explore the basis for this phenomenon, we have made recombinant histidyl-tRNA synthetase in the baculovirus system. It was enzymatically active and recognized by human autoantibodies. A truncated protein lacking the first 60 amino acids was inactive as an antigen and as an enzyme. This region is within the first two exons, is predicted to have a coiled-coil configuration, and is found in some other synthetases but not in Escherichia coli or yeast histidyl-tRNA synthetase. Circular dichroism showed that the peptides from this region (amino acids 1-60 and 1-47) have the predicted high a-helical content, but smaller fragments (1-30, 14-45, and 31-60) do not. The peptides with a high α-helical content could inhibit autoantibodies almost completely, whereas the smaller peptides were unable to do so. The amino acid sequence of this coiled-coil domain in human histidyl-tRNA synthetase resembles the sequence of the extended this coiled-coil arm near the NH2 terminus of bacterial seryl-tRNA synthetase as well as similar regions in some eukaryotic aminoacyl-tRNA synthetases, raising the possibility that this domain serves a similar tRNA-stabilizing role and has been preserved from a common ancestor.
AB - In myositis, disease-specific autoantibodies may be directed against an aminoacyl-tRNA synthetase, usually histidyl-tRNA synthetase. To explore the basis for this phenomenon, we have made recombinant histidyl-tRNA synthetase in the baculovirus system. It was enzymatically active and recognized by human autoantibodies. A truncated protein lacking the first 60 amino acids was inactive as an antigen and as an enzyme. This region is within the first two exons, is predicted to have a coiled-coil configuration, and is found in some other synthetases but not in Escherichia coli or yeast histidyl-tRNA synthetase. Circular dichroism showed that the peptides from this region (amino acids 1-60 and 1-47) have the predicted high a-helical content, but smaller fragments (1-30, 14-45, and 31-60) do not. The peptides with a high α-helical content could inhibit autoantibodies almost completely, whereas the smaller peptides were unable to do so. The amino acid sequence of this coiled-coil domain in human histidyl-tRNA synthetase resembles the sequence of the extended this coiled-coil arm near the NH2 terminus of bacterial seryl-tRNA synthetase as well as similar regions in some eukaryotic aminoacyl-tRNA synthetases, raising the possibility that this domain serves a similar tRNA-stabilizing role and has been preserved from a common ancestor.
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M3 - Article
C2 - 7523371
AN - SCOPUS:0027983773
SN - 0021-9258
VL - 269
SP - 24277
EP - 24283
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 39
ER -