FIG. 2.

Yeast two-hybrid results demonstrate relative interaction between selected GlnB* variants and NifA, DRAT, and NtrB. Strains expressing the proteins indicated were patched onto different plates that are increasingly restrictive for growth and therefore increasingly demanding of GlnB interaction with its receptors, from left to right. In the first four columns, the demand is for growth in SD medium without histidine and in the presence of increasing amounts of 3-amino-1,2,4-triazol (3-AT), a competitive inhibitor of His3 protein (9). The right column demands growth in the absence of adenine (−Ade). WT, wild type. The experiment was performed in quintuplicate, but only a single set of responses is shown.