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A proximal arginine R206 participates in switching of the Bradyrhizobium japonicum FixL oxygen sensor.

Gilles-Gonzalez MA, Caceres AI, Sousa EH, Tomchick DR, Brautigam C, Gonzalez C, Machius M
J Mol Biol 360 80-9 (2006)
Cited: 11 times
EuropePMC logo PMID: 16813836

Abstract

In oxygen-sensing PAS domains, a conserved polar residue on the proximal side of the heme cofactor, usually arginine or histidine, interacts alternately with the protein in the "on-state" or the heme edge in the "off-state" but does not contact the bound ligand directly. We assessed the contributions of this residue in Bradyrhizobium japonicum FixL by determining the effects of an R206A substitution on the heme-PAS structure, ligand affinity, and regulatory capacity. The crystal structures of the unliganded forms of the R206A and wild-type BjFixL heme-PAS domains were similar, except for a more ruffled porphyrin ring in R206A BjFixL and a relaxation of the H214 residue and heme propionate 7 due to their lost interactions. The oxygen affinity of R206A BjFixL (Kd approximately 350 microM) was 2.5 times lower than that of BjFixL, and this was due to a higher off-rate constant for the R206A variant. The enzymatic activities of the unliganded "on-state" forms, either deoxy or met-R206A BjFixL, were comparable to each other and slightly lower (twofold less) than those of the corresponding BjFixL species. The most striking difference between the two proteins was in the enzymatic activities of the liganded "off-state" forms. In particular, saturation with a regulatory ligand (the Fe(III) form with cyanide) caused a >2000-fold inhibition of the BjFixL phosphorylation of BjFixJ, but a 140-fold inhibition of this catalytic activity in R206A BjFixL. Thus, in oxygen-sensing PAS domains, the interactions of polar residues with the heme edge couple the heme-binding domain to a transmitter during signal transduction.

Reviews citing this publication (3)

  1. Bacterial sensor kinases: diversity in the recognition of environmental signals. Krell T, Lacal J, Busch A, Silva-Jiménez H, Guazzaroni ME, Ramos JL. Annu Rev Microbiol 64 539-559 (2010)
  2. Sensor domains of two-component regulatory systems. Cheung J, Hendrickson WA. Curr Opin Microbiol 13 116-123 (2010)
  3. Heme-based globin-coupled oxygen sensors: linking oxygen binding to functional regulation of diguanylate cyclase, histidine kinase, and methyl-accepting chemotaxis. Martínková M, Kitanishi K, Shimizu T. J Biol Chem 288 27702-27711 (2013)

Articles citing this publication (8)

  1. Design and signaling mechanism of light-regulated histidine kinases. Möglich A, Ayers RA, Moffat K. J Mol Biol 385 1433-1444 (2009)
  2. Differential function of lip residues in the mechanism and biology of an anthrax hemophore. Ekworomadu MT, Poor CB, Owens CP, Balderas MA, Fabian M, Olson JS, Murphy F, Bakkalbasi E, Honsa ES, He C, Goulding CW, Maresso AW. PLoS Pathog 8 e1002559 (2012)
  3. Novel FixL homologues in Chlamydomonas reinhardtii bind heme and O(2). Murthy UM, Wecker MS, Posewitz MC, Gilles-Gonzalez MA, Ghirardi ML. FEBS Lett 586 4282-4288 (2012)
  4. Target DNA stabilizes Mycobacterium tuberculosis DevR/DosR phosphorylation by the full-length oxygen sensors DevS/DosS and DosT. Sousa EHS, Gonzalez G, Gilles-Gonzalez MA. FEBS J 284 3954-3967 (2017)
  5. Role of conserved F(alpha)-helix residues in the native fold and stability of the kinase-inhibited oxy state of the oxygen-sensing FixL protein from Sinorhizobium meliloti. Reynolds MF, Ackley L, Blizman A, Lutz Z, Manoff D, Miles M, Pace M, Patterson J, Pozzessere N, Saia K, Sato R, Smith D, Tarves P, Weaver M, Sieg K, Lukat-Rodgers GS, Rodgers KR. Arch Biochem Biophys 485 150-159 (2009)
  6. The Heme-Based Oxygen Sensor Rhizobium etli FixL: Influence of Auxiliary Ligands on Heme Redox Potential and Implications on the Enzyme Activity. Honorio-Felício N, Carepo MS, de F Paulo T, de França Lopes LG, Sousa EH, Diógenes IC, Bernhardt PV. J Inorg Biochem 164 34-41 (2016)
  7. pH dependence of cyanide and imidazole binding to the heme domains of Sinorhizobium meliloti and Bradyrhizobium japonicum FixL. Bidwai AK, Ahrendt AJ, Sullivan JS, Vitello LB, Erman JE. J Inorg Biochem 153 88-102 (2015)
  8. Photoacoustic Calorimetry Studies of O2-Sensing FixL and (R200, I209) Variants from Sinorhizobium meliloti Reveal Conformational Changes Coupled to Ligand Photodissociation from the Heme-PAS Domain. Mokdad A, Ang E, Desciak M, Ott C, Vilbert A, Beddow O, Butuc A, Larsen RW, Reynolds MF. Biochemistry 63 116-127 (2024)


Related citations provided by authors (2)

  1. The regulatory status of the fixL- and fixJ-like genes in Bradyrhizobium japonicum may be different from that in Rhizobium meliloti.. Anthamatten D, Hennecke H Mol Gen Genet 225 38-48 (1991)
  2. A distal arginine in oxygen-sensing heme-PAS domains is essential to ligand binding, signal transduction, and structure.. Dunham CM, Dioum EM, Tuckerman JR, Gonzalez G, Scott WG, Gilles-Gonzalez MA Biochemistry 42 7701-8 (2003)

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