Conformational Changes and Loose Packing Promote E. Coli Tryptophanase Cold Lability.
Kogan, A., Gdalevsky, G.Y., Cohen-Luria, R., Goldgur, Y., Phillips, R.S., Parola, A.H., Almog, O.(2009) BMC Struct Biol 9: 65
- PubMed: 19814824 
- DOI: https://doi.org/10.1186/1472-6807-9-65
- Primary Citation of Related Structures:  
2V0Y, 2V1P - PubMed Abstract: 
Oligomeric enzymes can undergo a reversible loss of activity at low temperatures. One such enzyme is tryptophanase (Trpase) from Escherichia coli. Trpase is a pyridoxal phosphate (PLP)-dependent tetrameric enzyme with a Mw of 210 kD. PLP is covalently bound through an enamine bond to Lys270 at the active site. The incubation of holo E. coli Trpases at 2 degrees C for 20 h results in breaking this enamine bond and PLP release, as well as a reversible loss of activity and dissociation into dimers. This sequence of events is termed cold lability and its understanding bears relevance to protein stability and shelf life.
Organizational Affiliation: 
Department of Chemistry, Ben-Gurion University of the Negev, Beer-Sheva, Israel. annak@bgu.ac.il