The work outlined in this study attempts to add clarification to the information processing and regulatory principles of biological organisms. The chemotactic response of bacteria is chosen as a model system for sensory transduction. The biochemical events involved in transmitting the signal processing it, and determining output response, will be studied at the molecular level. The procedures involve recombinant DNA methods and purification of the relevant proteins. One intensive study is devoted to the structure and function of the receptor since it is used as a model for transmembrane signaling and the understanding of conformational changes in proteins. Localized mutagenesis and physical studies including X-ray crystallography will be applied to the receptor to reveal the mechanism by which information is transmitted from the outside to the inside of the cell through a relatively small transmembrane region. To understand regulatory principles more extensively, the Krebs cycle and glyoxylate bypass will be studied intensively, particularly the role of phosphorylation at the crucial branchpoint. Studies in mutation to key enzymes, pseudorevertant selection, and overproduction and underproduction of enzymes in key pathways by recombinant DNA methods will be used to clarify the system. In particular, the energy cost of covalent modification and how the """"""""price'' affects the design will be investigated. The second phosphorylation system which will be under intensive investigation will be the protein kinase-C system of the neuroblastoma cell, which will be studied to clarify not only the principles of a second messenger system but also to understand specifically how it operates in the neurons of the brain. Although the above are parts of distinct systems and can be studied individually, a pattern of similar covalent modification, conformational changes and feedback properties should help in allowing each system to provide insight into the other. It is hoped that general principles of regulation and of information processing will be clarified.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Method to Extend Research in Time (MERIT) Award (R37)
Project #
2R37DK009765-23
Application #
3482927
Study Section
Microbial Physiology and Genetics Subcommittee 2 (MBC)
Project Start
1977-12-01
Project End
1992-11-30
Budget Start
1987-12-01
Budget End
1988-11-30
Support Year
23
Fiscal Year
1988
Total Cost
Indirect Cost
Name
University of California Berkeley
Department
Type
Schools of Arts and Sciences
DUNS #
094878337
City
Berkeley
State
CA
Country
United States
Zip Code
94704
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Jeffery, C J; Koshland Jr, D E (1994) A single hydrophobic to hydrophobic substitution in the transmembrane domain impairs aspartate receptor function. Biochemistry 33:3457-63
Biemann, H P; Koshland Jr, D E (1994) Aspartate receptors of Escherichia coli and Salmonella typhimurium bind ligand with negative and half-of-the-sites cooperativity. Biochemistry 33:629-34
Shapiro, M J; Koshland Jr, D E (1994) Mutagenic studies of the interaction between the aspartate receptor and methyltransferase from Escherichia coli. J Biol Chem 269:11054-9
Morimoto, B H; Koshland Jr, D E (1994) Conditional activation of cAMP signal transduction by protein kinase C. The effect of phorbol esters on adenylyl cyclase in permeabilized and intact cells. J Biol Chem 269:4065-9
Jeffery, C J; Koshland Jr, D E (1993) Three-dimensional structural model of the serine receptor ligand-binding domain. Protein Sci 2:559-66
Yeh, J I; Biemann, H P; Pandit, J et al. (1993) The three-dimensional structure of the ligand-binding domain of a wild-type bacterial chemotaxis receptor. Structural comparison to the cross-linked mutant forms and conformational changes upon ligand binding. J Biol Chem 268:9787-92
Stoddard, B L; Koshland Jr, D E (1993) Molecular recognition analyzed by docking simulations: the aspartate receptor and isocitrate dehydrogenase from Escherichia coli. Proc Natl Acad Sci U S A 90:1146-53
Martin, P T; Chung, B T; Koshland Jr, D E (1993) Regulation of neurosecretory habituation by cAMP. Role of adaptation of cAMP signals. Eur J Biochem 217:259-65

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