Characterization of the molecular properties of KtrC, a second RCK domain that regulates a Ktr channel in Bacillus subtilis
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| Title: | Characterization of the molecular properties of KtrC, a second RCK domain that regulates a Ktr channel in Bacillus subtilis |
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| Authors: | Celso M. Teixeira-Duarte, Joao M.P. Jorge, João H. Morais-Cabral, Rita Gomes Rocha |
| Contributors: | Instituto de Investigação e Inovação em Saúde |
| Source: | Journal of Structural Biology. 205:34-43 |
| Publisher Information: | Elsevier BV, 2019. |
| Publication Year: | 2019 |
| Subject Terms: | Models, Molecular, Protein Conformation, alpha-Helical, 0301 basic medicine, Adenosine Triphosphate / metabolism, Recombinant Proteins / genetics, Amino Acid Motifs, Potassium / chemistry, Gene Expression, Crystallography, X-Ray, Adenosine Triphosphate, Adenosine Triphosphate / chemistry, Bacillus subtilis / chemistry, Genetic Vectors / chemistry, Cloning, Molecular, Cation Transport Proteins, 0303 health sciences, Recombinant Proteins / metabolism, Protein Isoforms / metabolism, Cations, Monovalent, Bacterial Proteins / chemistry, Adenosine Diphosphate, Protein Isoforms / genetics, Escherichia coli / metabolism, Adenosine Diphosphate / metabolism, Dinucleoside Phosphates, Bacillus subtilis, Protein Binding, Cation Transport Proteins / genetics, Bacillus subtilis / metabolism, Bacterial Proteins / genetics, Genetic Vectors, Potassium / metabolism, 03 medical and health sciences, Bacterial Proteins, Bacterial Proteins / metabolism, Genetic Vectors / metabolism, Escherichia coli, Protein Interaction Domains and Motifs, Recombinant Proteins / chemistry, Cation Transport Proteins / chemistry, Binding Sites, Ion Transport, Cation Transport Proteins / metabolism, Protein Isoforms / chemistry, Genetic Complementation Test, Escherichia coli / genetics, Adenosine Diphosphate / chemistry, Dinucleoside Phosphates / chemistry, Potassium, Protein Conformation, beta-Strand, Dinucleoside Phosphates / metabolism, Protein Multimerization |
| Description: | RCK (regulating conductance of K+) domains are common regulatory domains that control the activity of eukaryotic and prokaryotic K+ channels and transporters. In bacteria these domains play roles in osmoregulation, regulation of turgor and membrane potential and in pH homeostasis. Whole-genome sequencing unveiled RCK gene redundancy, however the biological role of this redundancy is not well understood. In Bacillus subtilis, there are two closely related RCK domain proteins (KtrA and KtrC) that regulate the activity of the Ktr cation channels. KtrA has been well characterized but little is known about KtrC. We have characterized the structural and biochemical proprieties of KtrC and conclude that KtrC binds ATP and ADP, just like KtrA. However, in solution KtrC exist in a dynamic equilibrium between octamers and non-octameric species that is dependent on the bound ligand, with ATP destabilizing the octameric ring relative to ADP. Accordingly, KtrC-ADP crystal structures reveal closed octameric rings similar to those in KtrA, while KtrC-ATP adopts an open assembly with RCK domains forming a super-helix. In addition, both KtrC-ATP and -ADP octamers are stabilized by the signaling molecule cyclic-di-AMP, which binds to KtrC with high affinity. In contrast, c-di-AMP binds with 100-fold lower affinity to KtrA. Despite these differences we show with an E. coli complementation assay that KtrC and KtrA are interchangeable and able to form functional transporters with both KtrB and KtrD. The distinctive properties of KtrC, in particular ligand-dependent assembly/disassembly, suggest that this protein has a specific physiological role that is distinct from KtrA. |
| Document Type: | Article |
| File Description: | application/pdf; application/vnd.openxmlformats-officedocument.wordprocessingml.document |
| Language: | English |
| ISSN: | 1047-8477 |
| DOI: | 10.1016/j.jsb.2019.02.002 |
| Access URL: | https://repositorio-aberto.up.pt/bitstream/10216/127799/1/10.1016-j.jsb.2019.02.002.pdf https://pubmed.ncbi.nlm.nih.gov/30753894 https://www.ncbi.nlm.nih.gov/pubmed/30753894 https://europepmc.org/abstract/MED/30753894 https://www.rcsb.org/structure/6i8v https://www.sciencedirect.com/science/article/pii/S1047847719300255 https://repositorio-aberto.up.pt/bitstream/10216/127799/1/10.1016-j.jsb.2019.02.002.pdf https://repositorio-aberto.up.pt/handle/10216/127799 https://hdl.handle.net/10216/127799 |
| Rights: | Elsevier TDM CC BY NC ND |
| Accession Number: | edsair.doi.dedup.....e5c1035abdb32c7d2461b5f26566d4c4 |
| Database: | OpenAIRE |
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Nájsť tento článok vo Web of Science | Abstract: | RCK (regulating conductance of K+) domains are common regulatory domains that control the activity of eukaryotic and prokaryotic K+ channels and transporters. In bacteria these domains play roles in osmoregulation, regulation of turgor and membrane potential and in pH homeostasis. Whole-genome sequencing unveiled RCK gene redundancy, however the biological role of this redundancy is not well understood. In Bacillus subtilis, there are two closely related RCK domain proteins (KtrA and KtrC) that regulate the activity of the Ktr cation channels. KtrA has been well characterized but little is known about KtrC. We have characterized the structural and biochemical proprieties of KtrC and conclude that KtrC binds ATP and ADP, just like KtrA. However, in solution KtrC exist in a dynamic equilibrium between octamers and non-octameric species that is dependent on the bound ligand, with ATP destabilizing the octameric ring relative to ADP. Accordingly, KtrC-ADP crystal structures reveal closed octameric rings similar to those in KtrA, while KtrC-ATP adopts an open assembly with RCK domains forming a super-helix. In addition, both KtrC-ATP and -ADP octamers are stabilized by the signaling molecule cyclic-di-AMP, which binds to KtrC with high affinity. In contrast, c-di-AMP binds with 100-fold lower affinity to KtrA. Despite these differences we show with an E. coli complementation assay that KtrC and KtrA are interchangeable and able to form functional transporters with both KtrB and KtrD. The distinctive properties of KtrC, in particular ligand-dependent assembly/disassembly, suggest that this protein has a specific physiological role that is distinct from KtrA. |
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| ISSN: | 10478477 |
| DOI: | 10.1016/j.jsb.2019.02.002 |