1n3l
Crystal structure of a human aminoacyl-tRNA synthetase cytokineCrystal structure of a human aminoacyl-tRNA synthetase cytokine
Structural highlights
Disease[SYYC_HUMAN] Defects in YARS are the cause of Charcot-Marie-Tooth disease dominant intermediate type C (CMTDIC) [MIM:608323]. CMTDIC is a form of Charcot-Marie-Tooth disease characterized by clinical and pathologic features intermediate between demyelinating and axonal peripheral neuropathies, and motor median nerve conduction velocities ranging from 25 to 45 m/sec.[1] Function[SYYC_HUMAN] Catalyzes the attachment of tyrosine to tRNA(Tyr) in a two-step reaction: tyrosine is first activated by ATP to form Tyr-AMP and then transferred to the acceptor end of tRNA(Tyr) (By similarity). Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe 20 aminoacyl-tRNA synthetases catalyze the first step of protein synthesis and establish the rules of the genetic code through aminoacylation reactions. Biological fragments of two human enzymes, tyrosyl-tRNA synthetase (TyrRS) and tryptophanyl-tRNA synthetase, connect protein synthesis to cell-signaling pathways including angiogenesis. Alternative splicing or proteolysis produces these fragments. The proangiogenic N-terminal fragment mini-TyrRS has IL-8-like cytokine activity that, like other CXC cytokines, depends on a Glu-Leu-Arg motif. Point mutations in this motif abolish cytokine activity. The full-length native TyrRS lacks cytokine activity. No structure has been available for any mammalian tRNA synthetase that, in turn, might give insight into why mini-TyrRS and not TyrRS has cytokine activities. Here, the structure of human mini-TyrRS, which contains both the catalytic and the anticodon recognition domain, is reported to a resolution of 1.18 A. The critical Glu-Leu-Arg motif is located on an internal alpha-helix of the catalytic domain, where the guanidino side chain of R is part of a hydrogen-bonding network tethering the anticodon-recognition domain back to the catalytic site. Whereas the catalytic domains of the human and bacterial enzymes superimpose, the spatial disposition of the anticodon recognition domain relative to the catalytic domain is unique in mini-TyrRS relative to the bacterial orthologs. This unique orientation of the anticodon-recognition domain can explain why the fragment mini-TyrRS, and not full-length native TyrRS, is active in cytokine-signaling pathways. Crystal structure of a human aminoacyl-tRNA synthetase cytokine.,Yang XL, Skene RJ, McRee DE, Schimmel P Proc Natl Acad Sci U S A. 2002 Nov 26;99(24):15369-74. Epub 2002 Nov 11. PMID:12427973[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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