1q8l
From Proteopedia
Revision as of 08:25, 24 February 2018
Second Metal Binding Domain of the Menkes ATPase
Structural highlights
Disease[ATP7A_HUMAN] Defects in ATP7A are the cause of Menkes disease (MNKD) [MIM:309400]; also known as kinky hair disease. MNKD is an X-linked recessive disorder of copper metabolism characterized by generalized copper deficiency. MNKD results in progressive neurodegeneration and connective-tissue disturbances: focal cerebral and cerebellar degeneration, early growth retardation, peculiar hair, hypopigmentation, cutis laxa, vascular complications and death in early childhood. The clinical features result from the dysfunction of several copper-dependent enzymes.[1] [2] [3] [4] [5] [6] [7] [8] [9] Defects in ATP7A are the cause of occipital horn syndrome (OHS) [MIM:304150]; also known as X-linked cutis laxa. OHS is an X-linked recessive disorder of copper metabolism. Common features are unusual facial appearance, skeletal abnormalities, chronic diarrhea and genitourinary defects. The skeletal abnormalities included occipital horns, short, broad clavicles, deformed radii, ulnae and humeri, narrowing of the rib cage, undercalcified long bones with thin cortical walls and coxa valga.[10] [11] Defects in ATP7A are a cause of distal spinal muscular atrophy X-linked type 3 (DSMAX3) [MIM:300489]. DSMAX3 is a neuromuscular disorder. Distal spinal muscular atrophy, also known as distal hereditary motor neuronopathy, represents a heterogeneous group of neuromuscular disorders 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.[12] Function[ATP7A_HUMAN] May supply copper to copper-requiring proteins within the secretory pathway, when localized in the trans-Golgi network. Under conditions of elevated extracellular copper, it relocalized to the plasma membrane where it functions in the efflux of copper from cells. 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 PubMedBiological utilisation of copper requires that the metal, in its ionic forms, be meticulously transported, inserted into enzymes and regulatory proteins, and excess be excreted. To understand the trafficking process, it is crucial that the structures of the proteins involved in the varied processes be resolved. To investigate copper binding to a family of structurally related copper-binding proteins, we have characterised the second Menkes N-terminal domain (MNKr2). The structure, determined using 1H and 15N heteronuclear NMR, of the reduced form of MNKr2 has revealed two alpha-helices lying over a single beta-sheet and shows that the binding site, a Cys(X)2Cys pair, is located on an exposed loop. 1H-15N HSQC experiments demonstrate that binding of Cu(I) causes changes that are localised to conserved residues adjacent to the metal binding site. Residues in this area are important to the delivery of copper by the structurally related Cu(I) chaperones. Complementary site-directed mutagenesis of the adjacent residues has been used to probe the structural roles of conserved residues. Structure and metal binding studies of the second copper binding domain of the Menkes ATPase.,Jones CE, Daly NL, Cobine PA, Craik DJ, Dameron CT J Struct Biol. 2003 Sep;143(3):209-18. PMID:14572476[13] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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