HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

J. Biol. Chem., Vol. 279, Issue 4, 2350-2359, January 23, 2004

This Article Full Text Full Text (PDF) All Versions of this Article: 279/4/2350    most recent M306181200v1 Submit a Letter to Editor Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Harrod, A. C. Articles by Reitzer, L. Search for Related Content PubMed PubMed Citation Articles by Harrod, A. C. Articles by Reitzer, L. Social Bookmarking                      What's this?

Evidence for a Second Interaction between the Regulatory Amino-terminal and Central Output Domains of the Response Regulator NtrC (Nitrogen Regulator I) in Escherichia coli^*

Albert Carson Harrod, Xiaofeng Yang, Matthew Junker, and Larry Reitzer

From the Molecular and Cell Biology Department, The University of Texas at Dallas, Richardson, Texas 75083-0688

Nitrogen limitation in Escherichia coli activates about 100 genes. Their expression requires the response regulator NtrC (also called nitrogen regulator I or NR_I). Phosphorylation of the amino-terminal domain (NTD) of NtrC activates the neighboring central domain and leads to transcriptional activation from promoters that require ⁵⁴-containing RNA polymerase. The NTD has five strands alternating with five helices. Phosphorylation of aspartate 54 has been shown to reposition helix 3 to strand 5 (the "3445 face") within the NTD. To further study the interactions between the amino-terminal and central domains, we isolated strains with alterations in the NTD that were able to grow on a poor nitrogen source in the absence of phosphorylation by the cognate sensor kinase. We identified strains with alterations located in the 3445 face and helix 5. Both types of alterations stimulated central domain activities. The helix 5 alterations differed from those in the 3445 face. They did not cause a large scale conformational change in the NTD, which is not necessary for transcriptional activation in these mutants. Yeast two-hybrid analysis indicated that substitutions in both helix 5 and the 3445 face diminish the interaction between the NTD and the central domain. Our results suggest that helix 5 of the NTD, in addition to the 3445 face, interacts with the central domain. We present a model of interdomain signal transduction that proposes different functions for helix 5 and the 3445 face.

Received for publication, June 11, 2003 , and in revised form, October 13, 2003.

Note Added in Proof—After this paper was accepted, a structure of the central domain of a homologous protein was published by Lee, S.-Y., Torre, A., Yan, D., Kustu, S., Nixon, B. T., and Wemmer, D. E. (2003) Genes Dev. 17, 2552–2563. Their paper also suggests that an important function of the amino-terminal regulatory domain is to control oligomerization of the central domain. There is no reason to suspect variation in the mechanism of oligomerization control among response regulators, e.g. for details, see Park, S., Zhang, H., Jones, A. D., and Nixon, B. T. (2002) Biochemistry 41, 10934–10941.

^* This work was supported by National Science Foundation Grant MCB-0077904 and National Institutes of Health Grant GM47965. The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

Both authors contributed equally to this work and should be considered co-first authors. Present address: Dept. of Microbiology, The University of Texas Southwestern Medical Center, Dallas, TX 75390-9048.

To whom correspondence should be addressed: Molecular and Cell Biology Dept., The University of Texas at Dallas, P. O. Box 830688, Richardson, TX 75083-0688. Tel.: 972-883-2502; Fax: 972-883-2409; E-mail: reitzer{at}utdallas.edu.

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

				Z. Zhang, G. Gosset, R. Barabote, C. S. Gonzalez, W. A. Cuevas, and M. H. Saier Jr. Functional Interactions between the Carbon and Iron Utilization Regulators, Crp and Fur, in Escherichia coli J. Bacteriol., February 1, 2005; 187(3): 980 - 990. [Abstract] [Full Text] [PDF]

				X. F. Yang, Y. Ji, B. L. Schneider, and L. Reitzer Phosphorylation-independent Dimer-Dimer Interactions by the Enhancer-binding Activator NtrC of Escherichia coli: A THIRD FUNCTION FOR THE C-TERMINAL DOMAIN J. Biol. Chem., August 27, 2004; 279(35): 36708 - 36714. [Abstract] [Full Text] [PDF]