Sandbox Reserved 1070: Difference between revisions
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== Structural Overview == | == Structural Overview == | ||
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> | 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. [1]. The domain has an important role in signal transduction of bacteria[1]. 30 small bacterial proteins of family PRK0984 from differing strands of ''E. coli'' contain a CZB domain N-terminal to a GGDEF domain[1]. 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. 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. | ||
===Catalytic GGEEF Domain=== | ===Catalytic GGEEF Domain=== | ||
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Diguanylate cyclases only function efficiently as dimers, to bind both GGDEF domains holding the substrates. The presence of Zinc disrupts the ability of the two domains to overlap. | Diguanylate cyclases only function efficiently as dimers, to bind both GGDEF domains holding the substrates. The presence of Zinc disrupts the ability of the two domains to overlap. | ||
1. The enzyme coordinates the substrate GTP to allow for deprotonation of the C3 -OH groups of the ribose. The negatively charged Oxygens on the phosphate groups of GTP are stabilized by | 1. The enzyme coordinates the substrate GTP to allow for deprotonation of the C3 -OH groups of the ribose. The negatively charged Oxygens on the phosphate groups of GTP are stabilized by Mg<sup>2+</sup> ions. | ||
2. The deprotonated Oxygen then acts as a nucleophile to attack the 𝝰phosphate of GTP. | 2. The deprotonated Oxygen then acts as a nucleophile to attack the 𝝰phosphate of GTP. | ||