Distinct functions of N and C-terminal domains of GreA, an Escherichia coli transcript cleavage factor.

摘要: The prokaryotic transcription factors GreA and GreB are involved in the regulation of transcript elongation by RNA polymerase (RNAP). Their known activities include suppression arrest, enhancement fidelity, facilitation transition from abortive initiation to productive elongation. Presumably, Gre proteins exert their functions altering conformation enzyme ternary complexes (TEC) inducing cleavage nascent RNA. have a similar structural organization consist two domains: C-terminal globular an extended N-terminal coiled-coil domain. To investigate functional roles domains, we expressed separately N domains (NTD CTD, respectively) characterized with vitro assays. We demonstrate that NTD possesses residual activity wild-type GreA. CTD does not display any nucleolytic activity; however, it substantially increases NTD. In contrast NTD, competes for binding RNAP inhibits antiarrest activities. Both individually together inhibit From these results conclude is responsible induction while determines RNAP. required full