4g85
From Proteopedia
Crystal structure of human HisRS
Structural highlights
Disease[SYHC_HUMAN] Defects in HARS are a cause of Usher syndrome type 3B (USH3B) [MIM:614504]. USH3B is a syndrome characterized by progressive vision and hearing loss during early childhood. Some patients have the so-called 'Charles Bonnet syndrome,' involving decreased visual acuity and vivid visual hallucinations. USH is a genetically heterogeneous condition characterized by the association of retinitis pigmentosa with sensorineural deafness. Age at onset and differences in auditory and vestibular function distinguish Usher syndrome type 1 (USH1), Usher syndrome type 2 (USH2) and Usher syndrome type 3 (USH3). USH3 is characterized by postlingual, progressive hearing loss, variable vestibular dysfunction, and onset of retinitis pigmentosa symptoms, including nyctalopia, constriction of the visual fields, and loss of central visual acuity, usually by the second decade of life.[1] Note=HARS mutations may be involved in peripheral neuropathy, a disease mainly characterized by distal motor and sensory dysfunction. Inherited peripheral neuropathies are clinically and genetically heterogeneous with variable age of onset and reduced penetrance associated with specific loci. HARS mutations may directly predispose patients to peripheral neuropathy or may modify a peripheral neuropathy phenotype by contributing to the genetic and environmental load in a given patient (PubMed:22930593). FunctionPublication Abstract from PubMedAminoacyl-tRNA synthetases (AARSs) catalyze aminoacylation of tRNAs in the cytoplasm. Surprisingly, AARSs also have critical extracellular and nuclear functions. Evolutionary pressure for new functions might be manifested by splice variants that skip only an internal catalytic domain (CD) and link noncatalytic N- and C-terminal polypeptides. Using disease-associated histidyl-tRNA synthetase (HisRS) as an example, we found an expressed 171-amino acid protein (HisRSDeltaCD) that deleted the entire CD, and joined an N-terminal WHEP to the C-terminal anticodon-binding domain (ABD). X-ray crystallography and three-dimensional NMR revealed the structures of human HisRS and HisRSDeltaCD. In contrast to homodimeric HisRS, HisRSDeltaCD is monomeric, where rupture of the ABD's packing with CD resulted in a dumbbell-like structure of flexibly linked WHEP and ABD domains. In addition, the ABD of HisRSDeltaCD presents a distinct local conformation. This natural internally deleted HisRS suggests evolutionary pressure to reshape AARS tertiary and quaternary structures for repurposing. Internally Deleted Human tRNA Synthetase Suggests Evolutionary Pressure for Repurposing.,Xu Z, Wei Z, Zhou JJ, Ye F, Lo WS, Wang F, Lau CF, Wu J, Nangle LA, Chiang KP, Yang XL, Zhang M, Schimmel P Structure. 2012 Sep 5;20(9):1470-7. PMID:22958643[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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Categories: Histidine--tRNA ligase | Homo sapiens | Schimmel, P | Wei, Z | Wu, J | Yang, X L | Zhang, M | Zhou, J J | Ligase | Synthetase
