title: Structural and functional analysis of the GerD spore germination protein of Bacillus species.
abstract: Spore germination in Bacillus species represents an excellent model system with which to study the molecular mechanisms underlying the nutritional control of growth and development. Binding of specific chemical nutrients to their cognate receptors located in the spore inner membrane triggers the germination process that leads to a resumption of metabolism in spore outgrowth. Recent studies suggest that the inner membrane GerD lipoprotein plays a critical role in the receptor-mediated activation of downstream germination events. The 121-residue core polypeptide of GerD (GerD⁶⁰⁻¹⁸⁰) from Geobacillus stearothermophilus forms a stable α-helical trimer in aqueous solution. The 2.3-Å-resolution crystal structure of the trimer reveals a neatly twisted superhelical rope, with unusual supercoiling induced by parallel triple-helix interactions. The overall geometry comprises three interleaved hydrophobic screws of interacting helices linked by short turns that have not been seen before. Using complementation analysis in a series of Bacillus subtilis gerD mutants, we demonstrated that alterations in the GerD trimer structure have profound effects on nutrient germination. This important structure-function relationship of trimeric GerD is supported by our identification of a dominant negative gerD mutation in B. subtilis. These results and those of others lead us to propose that GerD mediates clustering of germination proteins in the inner membrane of dormant spores and thus promotes the rapid and cooperative germination response to nutrients.
authors: Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, CT 06030-3305, USA.
authors: Yunfeng
authors: Y
authors: Li
authors: Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, CT 06030-3305, USA.
authors: Kai
authors: K
authors: Jin
authors: Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, CT 06030-3305, USA.
authors: Sonali
authors: S
authors: Ghosh
authors: Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, CT 06030-3305, USA.
authors: Parvathimadhavi
authors: P
authors: Devarakonda
authors: Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, CT 06030-3305, USA.
authors: Kristina
authors: K
authors: Carlson
authors: Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, CT 06030-3305, USA.
authors: Andrew
authors: A
authors: Davis
authors: Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, CT 06030-3305, USA.
authors: Kerry-Ann V
authors: KA
authors: Stewart
authors: Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, CT 06030-3305, USA.
authors: Elizabeth
authors: E
authors: Cammett
authors: Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, CT 06030-3305, USA.
authors: Patricia
authors: P
authors: Pelczar Rossi
authors: Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, CT 06030-3305, USA.
authors: Barbara
authors: B
authors: Setlow
authors: Public Health Research Institute Center, Department of Microbiology and Molecular Genetics, New Jersey Medical School, Rutgers University, Newark, NJ 07103, USA.
authors: Min
authors: M
authors: Lu
authors: Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, CT 06030-3305, USA.
authors: Peter
authors: P
authors: Setlow
authors: Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, CT 06030-3305, USA. Electronic address: bhao@uchc.edu.
authors: Bing
authors: B
authors: Hao
mesh_terms: D000595:Amino Acid Sequence; D001412:Bacillus subtilis / Q000737:chemistry / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D018360:Crystallography, X-Ray; D004252:DNA Mutational Analysis; D005816:Genetic Complementation Test; D001411:Geobacillus stearothermophilus / Q000737:chemistry / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D008074:Lipoproteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011487:Protein Conformation; D055503:Protein Multimerization; D016415:Sequence Alignment; D013171:Spores, Bacterial / Q000737:chemistry / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D008074:Lipoproteins; D008565:Membrane Proteins
keywords: Bacillus; GerD; germinant receptors; spore germination; spores