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Crystal structure of the N-domain of HMA8, a copper-transporting P-type ATPase
Structural highlights
FunctionHMA8_ARATH Mediates copper transfer across the chloroplast thylakoid membrane. Required for copper delivery into the thylakoids lumen, which is essential for the function of copper proteins.[1] Publication Abstract from PubMedCopper is a crucial ion in cells, but needs to be closely controlled due to its toxic potential and ability to catalyse the formation of radicals. In chloroplasts, an important step for the proper functioning of the photosynthetic electron transfer chain is the delivery of copper to plastocyanin in the thylakoid lumen. The main route for copper transport to the thylakoid lumen is driven by two PIB-type ATPases, Heavy Metal ATPase 6 (HMA6) and HMA8, located in the inner membrane of the chloroplast envelope and in the thylakoid membrane, respectively. Here, the crystal structures of the nucleotide binding domain of HMA6 and HMA8 from Arabidopsis thaliana are reported at 1.5A and 1.75A resolution, respectively, providing the first structural information on plants Cu+-ATPases. The structures reveal a compact domain, with two short helices on both sides of a twisted beta-sheet. A double mutant, aiding in the crystallization, provides a new crystal contact, but also avoids an internal clash highlighting the benefits of construct modifications. Finally, the histidine in the HP motif of the isolated domains, unable to bind ATP, shows a side chain conformation distinct from nucleotide bound structures. Structural Insights into the Nucleotide-Binding Domains of the P1B-type ATPases HMA6 and HMA8 from Arabidopsis thaliana.,Mayerhofer H, Sautron E, Rolland N, Catty P, Seigneurin-Berny D, Pebay-Peyroula E, Ravaud S PLoS One. 2016 Nov 1;11(11):e0165666. doi: 10.1371/journal.pone.0165666., eCollection 2016. PMID:27802305[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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