DC Field | Value | Language |
dc.contributor.author | Haenelt, Inga | |
dc.contributor.author | Loechte, Sara | |
dc.contributor.author | Sundermann, Lea | |
dc.contributor.author | Elbers, Katharina | |
dc.contributor.author | Vor der Brueggen, Marc | |
dc.contributor.author | Bakker, Evert P. | |
dc.date.accessioned | 2021-12-23T16:00:12Z | - |
dc.date.available | 2021-12-23T16:00:12Z | - |
dc.date.issued | 2010 | |
dc.identifier.uri | https://osnascholar.ub.uni-osnabrueck.de/handle/unios/4280 | - |
dc.description.abstract | KtrB, the K+-translocating subunit of the Na+-dependent bacterial K+ uptake system KtrAB, consists of four M1PM2 domains, in which M-1 and M-2 are transmembrane helices and P indicates a p-loop that folds back from the external medium into the cell membrane. The transmembrane stretch M-2C is, with its 40 residues, unusually long. It consists of three parts, the hydrophobic helices M-2C1 and M-2C3, which are connected by a nonhelical M-2C2 region, containing conserved glycine, alanine, serine, threonine, and lysine residues. Several point mutations in M-2C2 led to a huge gain of function of K+ uptake by KtrB from the bacterium Vibrio alginolyticus. This effect was exclusively due to an increase in V-max for K+ transport. Na+ translocation by KtrB was not affected. Partial to complete deletions of M-2C2 also led to enhanced Vmax values for K+ uptake via KtrB. However, several deletion variants also exhibited higher Km values for K+ uptake and at least one deletion variant, KtrB(Delta 326-328), also transported Na+ faster. The presence of KtrA did not suppress any of these effects. For the deletion variants, this was due to a diminished binding of KtrA to KtrB. PhoA studies indicated that M-2C2 forms a flexible structure within the membrane allowing M-2C3 to be directed either to the cytoplasm or (artificially) to the periplasm. These data are interpreted to mean (i) that region M-2C2 forms a flexible gate controlling K+ translocation at the cytoplasmic side of KtrB, and (ii) that M-2C2 is required for the interaction between KtrA and KtrB. | |
dc.description.sponsorship | Deutsche ForschungsgemeinschaftGerman Research Foundation (DFG); [SFB431]; This work was supported by SFB431, Teilprojekt P6 from the Deutsche Forschungsgemeinschaft. | |
dc.language.iso | en | |
dc.publisher | AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC | |
dc.relation.ispartof | JOURNAL OF BIOLOGICAL CHEMISTRY | |
dc.subject | ADAPTATION | |
dc.subject | AMINO-ACID SUBSTITUTIONS | |
dc.subject | Biochemistry & Molecular Biology | |
dc.subject | CHANNEL | |
dc.subject | ESCHERICHIA-COLI K-12 | |
dc.subject | GLYCINE RESIDUES | |
dc.subject | HIGH-AFFINITY | |
dc.subject | KDPFABC COMPLEX | |
dc.subject | POTASSIUM-TRANSPORT | |
dc.subject | PROTEIN | |
dc.subject | SELECTIVITY | |
dc.title | Gain of Function Mutations in Membrane Region M-2C2 of KtrB Open a Gate Controlling K+ Transport by the KtrAB System from Vibrio alginolyticus | |
dc.type | journal article | |
dc.identifier.doi | 10.1074/jbc.M109.089870 | |
dc.identifier.isi | ISI:000276264600016 | |
dc.description.volume | 285 | |
dc.description.issue | 14 | |
dc.description.startpage | 10318 | |
dc.description.endpage | 10327 | |
dc.contributor.orcid | 0000-0003-1495-3163 | |
dc.contributor.researcherid | N-2982-2016 | |
dc.identifier.eissn | 1083351X | |
dc.publisher.place | 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3996 USA | |
dcterms.isPartOf.abbreviation | J. Biol. Chem. | |
dcterms.oaStatus | Green Published, hybrid | |