title: Cyclic-di-GMP binding induces structural rearrangements in the PlzA and PlzC proteins of the Lyme disease and relapsing fever spirochetes: a possible switch mechanism for c-di-GMP-mediated effector functions.
abstract: The c-di-GMP network of Borrelia burgdorferi, a causative agent of Lyme disease, consists of Rrp1, a diguanylate cyclase/response regulator; Hpk1, a histidine kinase; PdeA and PdeB, c-di-GMP phosphodiesterases; and PlzA, a PilZ domain c-di-GMP receptor. Borrelia hermsii, a causative agent of tick-borne relapsing fever, possesses a putative c-di-GMP regulatory network that is uncharacterized. While B. burgdorferi requires c-di-GMP to survive within ticks, the associated effector mechanisms are poorly defined. Using site-directed mutagenesis, size exclusion chromatography, isothermal titration calorimetry and fluorescence resonance energy transfer, we investigate the interaction of c-di-GMP with the Borrelia PilZ domain-containing Plz proteins: B. burgdorferi PlzA and B. hermsii PlzC. The Plz proteins were determined to be monomeric in their apo and holo forms and to bind c-di-GMP with high affinity with a 1:1 stoichiometry. C-di-GMP binding induced structural rearrangements in PlzA and PlzC. C-di-GMP binding proved to be dependent on positive charge at R145of the PilZ domain motif, R145xxxR. Comparative sequence analyses led to the identification of Borrelia consensus sequences for the PilZ domain signature motifs. This study provides insight into c-di-GMP:Plz receptor interaction and identifies a possible switch mechanism that may regulate Plz protein effector functions.
authors.affiliation: Department of Microbiology and Immunology, Virginia Commonwealth University Medical Center, Richmond, VA 23298-0678, USA.
authors.forename: Katherine L
authors.initials: KL
authors.lastname: Mallory
authors.affiliation: Department of Microbiology and Immunology, Virginia Commonwealth University Medical Center, Richmond, VA 23298-0678, USA.
authors.forename: Daniel P
authors.initials: DP
authors.lastname: Miller
authors.affiliation: Department of Microbiology and Immunology, Virginia Commonwealth University Medical Center, Richmond, VA 23298-0678, USA.
authors.forename: Lee D
authors.initials: LD
authors.lastname: Oliver
authors.affiliation: Department of Microbiology and Immunology, Virginia Commonwealth University Medical Center, Richmond, VA 23298-0678, USA.
authors.forename: John C
authors.initials: JC
authors.lastname: Freedman
authors.affiliation: Department of Microbiology and Immunology, Virginia Commonwealth University Medical Center, Richmond, VA 23298-0678, USA.
authors.forename: Jessica L
authors.initials: JL
authors.lastname: Kostick-Dunn
authors.affiliation: Department of Microbiology and Immunology, Virginia Commonwealth University Medical Center, Richmond, VA 23298-0678, USA.
authors.forename: Jason A
authors.initials: JA
authors.lastname: Carlyon
authors.affiliation: Department of Chemistry and Biochemistry, University of California-San Diego, San Diego, CA 92110-8001, USA.
authors.forename: James D
authors.initials: JD
authors.lastname: Marion
authors.affiliation: University of California-San Diego, San Diego, CA 92110-8001, USA.
authors.forename: Jessica K
authors.initials: JK
authors.lastname: Bell
authors.affiliation: Department of Microbiology and Immunology, Virginia Commonwealth University Medical Center, Richmond, VA 23298-0678, USA richard.marconi@vcuhealth.org.|Center for Study of Biological Complexity, Virginia Commonwealth University Medical Center, Richmond, VA 23298-0678, USA.
authors.forename: Richard T
authors.initials: RT
authors.lastname: Marconi
mesh_terms: D019943:Amino Acid Substitution; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D025065:Borrelia burgdorferi / Q000235:genetics / Q000378:metabolism; D006152:Cyclic GMP / Q000031:analogs & derivatives* / Q000378:metabolism; D006801:Humans; D008193:Lyme Disease / Q000382:microbiology*; D009154:Mutation; D011485:Protein Binding; D011487:Protein Conformation; D055503:Protein Multimerization; D012061:Relapsing Fever / Q000382:microbiology*; D013143:Spirochaetaceae / Q000235:genetics / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; C062025:bis(3',5')-cyclic diguanylic acid; D006152:Cyclic GMP
keywords: Lyme disease; PlzA, Borrelia; Rrp1; c-di-GMP; relapsing fever