4kr2 | pdb_00004kr2
Glycyl-tRNA synthetase in complex with tRNA-Gly
Structural highlights
Disease[SYG_HUMAN] Defects in GARS are the cause of Charcot-Marie-Tooth disease type 2D (CMT2D) [MIM:601472]. CMT2D is a form of Charcot-Marie-Tooth disease, the most common inherited disorder of the peripheral nervous system. Charcot-Marie-Tooth disease is classified in two main groups on the basis of electrophysiologic properties and histopathology: primary peripheral demyelinating neuropathy or CMT1, and primary peripheral axonal neuropathy or CMT2. Neuropathies of the CMT2 group are characterized by signs of axonal regeneration in the absence of obvious myelin alterations, normal or slightly reduced nerve conduction velocities, and progressive distal muscle weakness and atrophy. CMT2D is characterized by a more severe phenotype in the upper extremities (severe weakness and atrophy, absence of tendon reflexes) than in the lower limbs. CMT2D inheritance is autosomal dominant.[1] Defects in GARS are a cause of distal hereditary motor neuronopathy type 5A (HMN5A) [MIM:600794]; also known as distal hereditary motor neuropathy type V (DSMAV). A disorder characterized by distal muscular atrophy mainly affecting the upper extremities, in contrast to other distal motor neuronopathies. These constitute a heterogeneous group of neuromuscular diseases caused by selective degeneration of motor neurons in the anterior horn of the spinal cord, without sensory deficit in the posterior horn. The overall clinical picture consists of a classical distal muscular atrophy syndrome in the legs without clinical sensory loss. The disease starts with weakness and wasting of distal muscles of the anterior tibial and peroneal compartments of the legs. Later on, weakness and atrophy may expand to the proximal muscles of the lower limbs and/or to the distal upper limbs.[2] Function[SYG_HUMAN] Catalyzes the attachment of glycine to tRNA(Gly). Is also able produce diadenosine tetraphosphate (Ap4A), a universal pleiotropic signaling molecule needed for cell regulation pathways, by direct condensation of 2 ATPs.[3] Publication Abstract from PubMedAminoacyl-tRNA synthetases are an ancient enzyme family that specifically charges tRNA molecules with cognate amino acids for protein synthesis. Glycyl-tRNA synthetase (GlyRS) is one of the most intriguing aminoacyl-tRNA synthetases due to its divergent quaternary structure and abnormal charging properties. In the past decade, mutations of human GlyRS (hGlyRS) were also found to be associated with Charcot-Marie-Tooth disease. However, the mechanisms of traditional and alternative functions of hGlyRS are poorly understood due to a lack of studies at the molecular basis. In this study we report crystal structures of wild type and mutant hGlyRS in complex with tRNA and with small substrates and describe the molecular details of enzymatic recognition of the key tRNA identity elements in the acceptor stem and the anticodon loop. The cocrystal structures suggest that insertions 1 and 3 work together with the active site in a cooperative manner to facilitate efficient substrate binding. Both the enzyme and tRNA molecules undergo significant conformational changes during glycylation. A working model of multiple conformations for hGlyRS catalysis is proposed based on the crystallographic and biochemical studies. This study provides insights into the catalytic pathway of hGlyRS and may also contribute to our understanding of Charcot-Marie-Tooth disease. Cocrystal Structures of Glycyl-tRNA Synthetase in Complex with tRNA Suggest Multiple Conformational States in Glycylation.,Qin X, Hao Z, Tian Q, Zhang Z, Zhou C, Xie W J Biol Chem. 2014 Jul 18;289(29):20359-69. doi: 10.1074/jbc.M114.557249. Epub, 2014 Jun 4. PMID:24898252[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
Contents | ||||||||||||||||||||||||
