A PII-like protein regulated by bicarbonate: structural and biochemical studies of the carboxysome-associated CPII protein
| Autor: | Todd O. Yeates, Kevin D. Eden, Hamidreza Hoveida, Justin Rosinski, Duilio Cascio, Wayne L. Hubbell, Joanna Ngo, Michael Collazo, Nicole M. Wheatley, Michael R. Sawaya |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2016 |
| Předmět: |
0301 basic medicine
Models Molecular Operon Protein Conformation Bicarbonate Allosteric regulation Biology Crystallography X-Ray Article 03 medical and health sciences chemistry.chemical_compound Bacterial Proteins Structural Biology Nucleotide Molecular Biology chemistry.chemical_classification 030102 biochemistry & molecular biology Betaproteobacteria biology.organism_classification Transmembrane protein Adenosine Diphosphate Carboxysome Bicarbonates 030104 developmental biology Biochemistry chemistry Intracellular Bacteria Protein Binding |
| Popis: | Autotrophic bacteria rely on various mechanisms to increase intracellular concentrations of inorganic forms of carbon (i.e. bicarbonate and CO2) in order to improve the efficiency with which they can be converted to organic forms. Transmembrane bicarbonate transporters and carboxysomes play key roles in accumulating bicarbonate and carbon dioxide, but other regulatory elements of carbon concentration mechanisms in bacteria are less understood. In this study, after analyzing the genomic regions around α-type carboxysome operons, we characterize a protein that is conserved across these operons but which has not been previously studied. On the basis of a series of apo- and ligand-bound crystal structures and supporting biochemical data, we show that this protein, which we refer to as the carboxysome-associated PII protein (CPII), represents a new and distinct subfamily within the broad superfamily of previously studied PII regulatory proteins, which are generally involved in regulating nitrogen metabolism in bacteria. CPII undergoes dramatic conformational changes in response to ADP binding, and the affinity for nucleotide binding is strongly enhanced by the presence of bicarbonate. CPII therefore appears to be a unique type of PII protein that senses bicarbonate availability, consistent with its apparent genomic association with the carboxysome and its constituents. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|