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Julius Adler's Contributions to Understanding Bacterial Chemotaxis

2006; Elsevier BV; Volume: 281; Issue: 41 Linguagem: Inglês

10.1016/s0021-9258(19)89330-4

1083-351X

Nicole Kresge, Robert Simoni, Robert L. Hill,

Origins and Evolution of Life

Isolation of Glutamic Acid Methyl Ester from an Escherichia coli Membrane Protein Involved in Chemotaxis (Kleene, S. J., Toews, M. L., and Adler, J. (1977) J. Biol. Chem. 252, 3214–3218) Methanol Formation in Vivo from Methylated Chemotaxis Proteins in Escherichia coli (Toews, M. L., and Adler, J. (1979) J. Biol. Chem. 254, 1761–1764) Bacterial Cell Envelopes with Functional Flagella (Eisenbach, M., and Adler, J. (1981) J. Biol. Chem. 256, 8807–8814) Julius Adler was born in Edelfingen, Germany in 1930. He attended Harvard University and received his A.B. in Biochemical Sciences in 1952. He then went to the University of Wisconsin-Madison where he studied with Journal of Biological Chemistry (JBC) Classics author Henry A. Lardy (1Lardy H.A. Ziegler J.A. JBC ClassicsJ. Biol. Chem. 1945; 159: 343-351Abstract Full Text PDF Google ScholarLardy H.A. Wiebelhaus V.D. Mann K.M. J. Biol. Chem. 1950; 187: 325-337Abstract Full Text PDF PubMed Google ScholarLardy H.A. Wellman H. J. Biol. Chem. 1952; 195: 215-224http://www.jbc.org/cgi/content/full/280/21/e17Abstract Full Text PDF PubMed Google Scholar) and earned an M.S. in Biochemistry in 1954 and a Ph.D. in Biochemistry in 1957. After graduating, Adler did postdoctoral fellowships with JBC Classics author Arthur Kornberg (2Lehman I.R. Bessman M.J. Simms E.S. Kornberg A. JBC ClassicsJ. Biol. Chem. 1958; 233: 163-170Abstract Full Text PDF PubMed Google ScholarBessman M.J. Lehman I.R. Simms E.S. Kornberg A. J. Biol. Chem. 1958; 233: 171-177http://www.jbc.org/cgi/content/full/280/49/e46Abstract Full Text PDF PubMed Google Scholar) in the Department of Microbiology at Washington University School of Medicine (1957–1959) and A. Dale Kaiser in the Department of Biochemistry at Stanford University School of Medicine (1959–1960). Adler then returned to the University of Wisconsin-Madison and joined the faculty of the Departments of Biochemistry and Genetics as an Assistant Professor. In 1963 he was promoted to Associate Professor, and in 1966 he became Professor. Adler became Edwin Bret Hart Professor in 1972 and was Steenbock Professor of Microbiological Sciences from 1982 to 1992. He became an Emeritus Professor in the Departments of Biochemistry and Genetics in 1997 and remains in that capacity today. Since he was a child, Adler had been fascinated with the question of how organisms sense and respond to their environment. After returning to the University of Wisconsin-Madison, he started looking for a system that would lend itself to the study of this question. He found this system in Escherichia coli. Scientists had already shown that bacteria were attracted to favorable chemical environments such as ones containing galactose and repulsed by unfavorable environments. However, the molecular mechanisms of chemotaxis were still entirely unknown in the 1960s. Using E. coli, Adler showed that bacteria sensed attractants and repellants with sensory proteins he termed chemoreceptors (3Adler J. Chemoreceptors in bacteria.Science. 1969; 166: 1588-1597Crossref PubMed Scopus (418) Google Scholar). These initial findings led to Adler's discovery that the methylation of a protein in the envelope of E. coli is involved in chemotaxis (4Kort E.N. Goy M.F. Larsen S.H. Adler J. Methylation of a membrane protein involved in bacterial chemotaxis.Proc. Natl. Acad. Sci. U. S. A. 1975; 72: 3939-3943Crossref PubMed Scopus (148) Google Scholar). The protein, methyl-accepting chemotaxis protein (MCP), acquired methyl groups from methionine. In order to further study the methylation process and the involvement of MCP in chemotaxis, Adler identified the methylated residue of MCP. This is the subject of the first JBC Classic reprinted here. Originally, Adler and his colleagues tried to isolate the methylated moiety by submitting MCP to a standard acid hydrolysis. However, this resulted in a loss of the methyl groups of MCP as volatile material. To circumvent this problem, Adler used an enzymatic proteolysis. He first incubated E. coli with [methyl-3H]methionine and then digested it by successive treatment with three proteolytic enzymes. This resulted in the identification of [methyl-3H]glutamic acid 5-methyl ester. Adler eventually discovered that E. coli contain several MCPs, all of which play a central role in the chemotaxis sensory transduction system. Strains of bacteria lacking these proteins or the ability to methylate or demethylate them were unable to respond to stimuli. Adler also noted that an increase in the concentration of attractants led to an increase in the methylation level of MCPs, whereas a decrease in the concentration of attractants or an increase in the concentration of repellents led to a decrease in methylation level. In the second JBC Classic reprinted here, Adler identifies the product formed during MCP demethylation. By incubating E. coli with l-[methyl-3H]methionine to label the MCP methyl groups, Adler determined that the end product of MCP demethylation is methanol. By the early 1980s, Adler and other investigators had made a lot of progress in understanding chemotaxis. They had determined that bacterial chemotaxis resulted from the regulation of flagellar rotation by chemoreceptors. In the presence of increasing attractant, bacteria swam more smoothly due to a counterclockwise rotation of their flagella. In contrast, a gradient of decreasing attractant resulted in an increase in bacterial tumbling, produced by a clockwise flagellar rotation. In order to more fully understand the chemotactic mechanism, Adler decided to develop a flagellated subcellular system, the content of which could be changed at will. The isolation of cell envelopes with intact flagella from E. coli and Salmonella typhimurium is the subject of the final JBC Classic reprinted here. Adler was able to isolate the envelopes by incubating the bacteria with penicillin and then lysing them osmotically. He found that by adding artificial electron donors and an energy source, he could restore counterclockwise flagellar rotation. This suggested that the proton electrochemical potential was the driving force behind counterclockwise flagellar rotation, whereas clockwise rotation required a cytoplasmic component. Adler has received many awards and honors for his work on bacterial chemotaxis. These include the Pasteur Award Medal from the Illinois Society for Microbiology (1977), the Selman A. Waksman Award in Microbiology from the National Academy of Sciences (1980), the Otto-Warburg Medal from the German Society for Biological Chemistry (1986), the R. H. Wright Award in Olfactory Research from Simon Fraser University in Canada (1988), the Hilldale Award from the University of Wisconsin-Madison (1988), the Abbott-American Society for Microbiology Lifetime Achievement Award (1995), and the William C. Rose Award from the American Society for Biochemistry and Molecular Biology (1996). He was elected to the American Academy of Arts and Sciences in 1976 and the National Academy of Sciences in 1978.