CHEM 153C Final: Regulation of Glutamine Synthetase important points

• School: UCLA
• Department: Chemistry and Biochemistry
• Course: CHEM 153C
• Professor: Weiss Richard

Document Summary

Regulation of glutamine synthetase: feedback inhibition (nitrogen-sufficient conditions) Complex regulation of glutamine synthetase confirms important role in nitrogen metabolism. Ctp: nitrogen status (alternative pathways nitrogen assimilation) Ii) modulation of enzyme activity: sensitivity to [nh3] Iii) control of enzyme activity (escherichia coli enzyme) Role = n h3 assimilat ion and anabolism. Utp (+) a- kg and at p ( ) gln and pi. Role = glut amine synt hesis f or anabolism. Iv) control of gene expression (ntrc transcription factor) Uses sigma54 (produced when low [nh3] to facilitate utilization of alternative nitrogen sources) Transferase (+) a- kg and at p ( ) gln and pi. Anabolism: nitrogen sufficiency (rich) (low expression of glutamine synthetase) Pin terna l glna ntrb ntrc rho-independent terminator: nitrogen limitation (high expression of glutamine synthetase) mrnas. Two component sensor-response regulator systems mrna: autokinase sensor proteins (ntrb) (autophosphorylation of histidine residue) Transmitter domain (c-terminus: response regulators (ntrc) Binding motif: direct effect of ntrc-p (e. g. hut operon)