Sandbox Reserved 1072: Difference between revisions

The DgcZ protein has C2 symmetry composed of two domains. The catalytic glycine-glycine-glutamate-glutamate-phenylalanine (GGEEF) domain responsible for synthesizing c-di-GMP and the regulatory chemoreceptor zinc binding (CZB) domain comprising two zinc binding sites. DgcZ binds zinc with sub-femtomolar affinity. When zinc is bound, the CZB and GGEEF domains adopt conformations that inhibit DgcZ function ^[1]. Enzyme DgcZ has been co-crystallized with Zinc conforming it to its inactivated conformation. The CZB domain is common to many bacterial lineages, appearing most commonly in bacterial chemoreceptors involved in <span class="plainlinks">[https://en.wikipedia.org/wiki/Chemotaxis chemotaxis]</span>. The second most common group of CZB domains is that of DgcZ homologs. The domain has an important role in signal transduction of bacteria. Many bacterial proteins from differing strands of ''E. coli'' contain CZB and GGDEF domains^[2]. The GGEEF domain of DgcZ is common to this family of enzymes containing the GGDEF domain. ''E. coli'' DgcZ is a protein made of two domains each of which is a symmetric homodimer. It exhibits <scene name='69/694239/C2_symmetry/6'>C2</scene> symmetry down its central axis. The GGEEF domain is catalytic in that it contains the active sites used for cyclizing GTP into c-di-GMP. The CZB domain is used for ligand-mediated regulation of c-di-GMP production. Zinc binds as an allosteric inhibitor in coordination with four residues to shift the protein into an inactive conformation^[1].