biostudies-literaturePurohit RHHS | National Institutes of HealthNIDDK NIH HHSNIGMS NIH HHS2108-2113https://www.ebi.ac.uk/biostudies/studies/S-EPMC5834730biostudies-literatureUnknown115(9)The copper-transporting P_1B-ATPases, which play a key role in cellular copper homeostasis, have been divided traditionally into two subfamilies, the P_1B-1-ATPases or CopAs and the P_1B-3-ATPases or CopBs. CopAs selectively export Cu⁺ whereas previous studies and bioinformatic analyses have suggested that CopBs are specific for Cu²⁺ export. Biochemical and spectroscopic characterization of <i>Sphaerobacter thermophilus</i> CopB (<i>St</i>CopB) show that, while it does bind Cu²⁺, the binding site is not the prototypical P_1B-ATPase transmembrane site and does not involve sulfur coordination as proposed previously. Most important, <i>St</i>CopB exhibits metal-stimulated ATPase activity in response to Cu⁺, but not Cu²⁺, indicating that it is actually a Cu⁺ transporter. X-ray absorption spectroscopic studies indicate that Cu⁺ is coordinated by four sulfur ligands, likely derived from conserved cysteine and methionine residues. The histidine-rich N-terminal region of <i>St</i>CopB is required for maximal activity, but is inhibitory in the presence of divalent metal ions. Finally, reconsideration of the P_1B-ATPase classification scheme suggests that the P_1B-1- and P_1B-3-ATPase subfamilies both comprise Cu⁺ transporters. These results are completely consistent with the known presence of only Cu⁺ within the reducing environment of the cytoplasm, which should eliminate the need for a Cu²⁺ P_1B-ATPase.Proceedings of the National Academy of Sciences of the United States of AmericaCu⁺-specific CopB transporter: Revising P_1B-type ATPase classification.PMC5834730T32 GM0083825T32GM008382DK068139P41 GM103393GM58518GM111097R01 GM058518R35 GM118035R01 DK068139GM118035R01 GM111097Stemmler TLBatelu SPurohit RRoss MOHoffman BMRosenzweig ACKusowski AfalseCu⁺-specific CopB transporter: Revising P_1B-type ATPase classification.The copper-transporting P_1B-ATPases, which play a key role in cellular copper homeostasis, have been divided traditionally into two subfamilies, the P_1B-1-ATPases or CopAs and the P_1B-3-ATPases or CopBs. CopAs selectively export Cu⁺ whereas previous studies and bioinformatic analyses have suggested that CopBs are specific for Cu²⁺ export. Biochemical and spectroscopic characterization of <i>Sphaerobacter thermophilus</i> CopB (<i>St</i>CopB) show that, while it does bind Cu²⁺, the binding site is not the prototypical P_1B-ATPase transmembrane site and does not involve sulfur coordination as proposed previously. Most important, <i>St</i>CopB exhibits metal-stimulated ATPase activity in response to Cu⁺, but not Cu²⁺, indicating that it is actually a Cu⁺ transporter. X-ray absorption spectroscopic studies indicate that Cu⁺ is coordinated by four sulfur ligands, likely derived from conserved cysteine and methionine residues. The histidine-rich N-terminal region of <i>St</i>CopB is required for maximal activity, but is inhibitory in the presence of divalent metal ions. Finally, reconsideration of the P_1B-ATPase classification scheme suggests that the P_1B-1- and P_1B-3-ATPase subfamilies both comprise Cu⁺ transporters. These results are completely consistent with the known presence of only Cu⁺ within the reducing environment of the cytoplasm, which should eliminate the need for a Cu²⁺ P_1B-ATPase.2018-01-01T00:00:00Z2018 Feb2024-12-04T06:04:07.159Z2019-03-26T23:52:30ZS-EPMC58347302944041810.1073/pnas.1721783115