Abstract

The proposed research will investigate """"""""complex"""""""" bacterial chemoreceptors. For the enteric bacteria these are defined as receptors having two protein components: a periplasmic substrate-binding protein (BP) and a signal transducer, which spans the cytoplasmic membrane and recognizes substrate-bound BP. The transducer in turn generates a signal that is transmitted through the cytoplasm to the flagella. Four BP-transducer systems are known in E. coli: maltose-BP (MBP) and Tar, galactose-BP (GBP) and Trg, ribose-BP (RBP) and Trg, and dipeptide-BP (DBP) and Tap. Mutational analysis of MBP and Tar has identified within each protein possible sites of interaction. This information has led to the formulation of specific hypotheses about the MBP-Tar pair, which will be examined by site-directed mutagenesis and by measurements of binding affinities between mutant MBP and Tar proteins. The data now available suggest that the MBP-Tar and GBP-Trg interactions are fundamentally different and evolved independently. This prediction will be tested by producing a series of chemotactically defective GBP's that can be compared with mutant MBP's. Peptide chemotaxis involves a receptor system that may prove to be novel in many respects. It is the only known BP dependent chemoreceptor that does not have a sugar as its substrate. Also DBP (55kd) is much larger than the sugar-BP's (30-40kd). The genes coding for the dipeptide transport system will be cloned and their products characterized in an effort to clarify the relationship between dipeptide transport and chemotaxis. The relative effectiveness of individual peptides as chemo-attractants and as ligands for DBP will be compared, and the ability of toxic peptides to serve as attractants will be studied. Finally, a mutational analysis will be initiated to study the DBP-Tar interaction. A pilot project on another tack will explore the utility of GBP-hybrid proteins as vehicles for the export of eukaryotic polypeptides from bacterial cells.

  Funding Agency

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM039736-05
Application #
3296883
Study Section
Microbial Physiology and Genetics Subcommittee 2 (MBC)
Project Start
1988-04-01
Project End
1993-03-31
Budget Start
1992-04-01
Budget End
1993-03-31
Support Year
5
Fiscal Year
1992
Total Cost
Indirect Cost

  Institution

Name
Texas A&M University
Department
Type
Schools of Earth Sciences/Natur
DUNS #
City
College Station
State
TX
Country
United States
Zip Code
77845

  Publications

Adase, Christopher A; Draheim, Roger R; Rueda, Garrett et al. (2013) Residues at the cytoplasmic end of transmembrane helix 2 determine the signal output of the TarEc chemoreceptor. Biochemistry 52:2729-38
Adase, Christopher A; Draheim, Roger R; Manson, Michael D (2012) The residue composition of the aromatic anchor of the second transmembrane helix determines the signaling properties of the aspartate/maltose chemoreceptor Tar of Escherichia coli. Biochemistry 51:1925-32
Wright, Gus A; Crowder, Rachel L; Draheim, Roger R et al. (2011) Mutational analysis of the transmembrane helix 2-HAMP domain connection in the Escherichia coli aspartate chemoreceptor tar. J Bacteriol 193:82-90
Cantwell, Brian J; Manson, Michael D (2009) Protein domains and residues involved in the CheZ/CheAS interaction. J Bacteriol 191:5838-41
Lai, Run-Zhi; Bormans, Arjan F; Draheim, Roger R et al. (2008) The region preceding the C-terminal NWETF pentapeptide modulates baseline activity and aspartate inhibition of Escherichia coli Tar. Biochemistry 47:13287-95
Ward, Scott M; Bormans, Arjan F; Manson, Michael D (2006) Mutationally altered signal output in the Nart (NarX-Tar) hybrid chemoreceptor. J Bacteriol 188:3944-51
Draheim, Roger R; Bormans, Arjan F; Lai, Run-Zhi et al. (2006) Tuning a bacterial chemoreceptor with protein-membrane interactions. Biochemistry 45:14655-64
Draheim, Roger R; Bormans, Arjan F; Lai, Run-zhi et al. (2005) Tryptophan residues flanking the second transmembrane helix (TM2) set the signaling state of the Tar chemoreceptor. Biochemistry 44:1268-77
Lai, Run-Zhi; Manson, Josiah M B; Bormans, Arjan F et al. (2005) Cooperative signaling among bacterial chemoreceptors. Biochemistry 44:14298-307
Mao, Hanbin; Cremer, Paul S; Manson, Michael D (2003) A sensitive, versatile microfluidic assay for bacterial chemotaxis. Proc Natl Acad Sci U S A 100:5449-54

Showing the most recent 10 out of 18 publications