4qei
From Proteopedia
Two distinct conformational states of GlyRS captured in crystal lattice
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 PubMedGlycyl-tRNA synthetase (GlyRS) is the enzyme that covalently links glycine to cognate tRNA for translation. It is of great research interest because of its nonconserved quaternary structures, unique species-specific aminoacylation properties, and noncanonical functions in neurological diseases, but none of these is fully understood. We report two crystal structures of human GlyRS variants, in the free form and in complex with tRNA(Gly) respectively, and reveal new aspects of the glycylation mechanism. We discover that insertion 3 differs considerably in conformation in catalysis and that it acts like a "switch" and fully opens to allow tRNA to bind in a cross-subunit fashion. The flexibility of the protein is supported by molecular dynamics simulation, as well as enzymatic activity assays. The biophysical and biochemical studies suggest that human GlyRS may utilize its flexibility for both the traditional function (regulate tRNA binding) and alternative functions (roles in diseases). Large Conformational Changes of Insertion 3 in Human Glycyl-tRNA Synthetase (hGlyRS) during Catalysis.,Deng X, Qin X, Chen L, Jia Q, Zhang Y, Zhang Z, Lei D, Ren G, Zhou Z, Wang Z, Li Q, Xie W J Biol Chem. 2016 Mar 11;291(11):5740-52. doi: 10.1074/jbc.M115.679126. Epub 2016, Jan 21. PMID:26797133[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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