Difference between revisions of "Part:BBa K847041"

Latest revision as of 01:15, 4 October 2012

''Escherichia coli'' betaine aldehyde dehydrogenase (betB)

This gene encodes the second step in glycine betaine biosynthesis.

Glycine betaine is a chemical that prevents the aggregation of proteins at low temperatures and facilitates the process of maintaining membrane fluidity (Chattopadhyay 2006). Psychromonas ingrahamii, an especially cold-tolerant bacteria, grows exponentially at -12° C, and it is believed that the production of glycine betaine from choline is essential for it to maintain osmotic stability at this temperature. A pathway to produce glycine betaine also natively exists in E. coli, but is not upregulated enough to afford it the cold resistance of P. ingrahamii.

Glycine betaine also has been found to play an osmoprotectant role in E. coli, balancing the osmolarity of the cytoplasm when the cell is under osmotic stress (Cayley, Lewis, and Record 1992).

The gram-negative biocontrol agent Pantoea agglomerans was ineffective at controlling blue mold on fruits because of its low viability during the long periods of dehydration that it experienced during fruit processing (Bonaterra, Camps, and Montesinos 2005). Its effectiveness was significantly increased when it was engineered to accumulate both trehalose and glycine betaine during desiccation, and it was hypothesized that these osmoprotectants “operate through protection of membrane phospholipids by direct hydrogen bounding with phospolipid head groups maintaining the liquid crystal state and stabilising proteins by water replacement via hydrogen bounding” (Bonaterra, Camps, and Montesinos 2005).

Sequence and Features